! 


UNIVERSITY  FARM 


Minnesota  Plant  Life. 


MINA  IT 


PL 


JFK 


by 
v     Mac  Mil  Ian 


R  e  p  u  r  t     of    the     S  u  r  v  ey 

Botanical    Scries 

III 


8nivoI.s>bBn>.  aisrl  w  ,IUB<1  .13  "issn  snivel  A    (.sasiqaiJno-rt)     .1 
.id  '{d   rlqetsoloriq  e  moil      .arnorl    -liarlJ   sdum 


PLATE  I.  (Frontispiece.)  A  ravine  near  St.  Paul,  where  shade-loving 
plants  make  their  home.  From  a  photograph  by  Dr.  Francis 
Ramaley. 


MI  N  N  E  SO 


PLAINT  LIFE 


by 
Con  way    Mac  Mill  an 


Report    of    the     Survey 

Botanical    Series 

III 


Saint  Paul,    Minnesota 
October  30,    \8gg 


PUBLISHED  BY  AUTHORITY  OF  THE 
BOARD  OF  REGENTS  OF  THE  UNIVERSITY 

FOR 
THE  PEOPLE  OF  MINNESOTA 

Edition,  10, 000  copies 


Preface* 


|T  has  been  well  said  that  the  main  difficulties  with  the  book  on  popular 
science  are  that,  if  popular,  it  will  not  be  scientific,  and,  if  scientific,  it 
will  not  be  popular.  Yet,  notwithstanding  the  truth  thus  epigrammatically 
expressed,  I  am  venturing  to  put  forth  Minnesota  Plant  Life  as  a  book 
certainly  meriting  the  designation  of  popular,  in  so  far  as  it  is  addressed  to  an 
audience  not  composed  of  botanists,  and  at  the  same  time  scientific,  to  the  extent  at 
least  of  choosing  for  its  field  one  of  the  two  great  realms  of  living  things  the  king- 
dom of  plants. 

While  to  be  out  of  fashion  is  to  be  out  of  the  world,  I  have,  nevertheless,  resisted 
the  impulse  to  designate  this  volume  as  a  suitable  text-book  for  the  "secondary 
schools."  On  the  contrary,  such  a  use  of  it  would  be,  in  my  opinion,  distinctly  un- 
fortunate. It  is  not  written  in  pedagogical  vein,  nor  does  it  pre-suppose  an  acquaint- 
ance with  teachers  and  laboratories.  It  would,  however,  be  disingenuous  to  deny 
that  the  author  has  a  definite  educational  purpose  in  view.  Since  this  volume  is  to 
be  distributed  in  every  county  and  perhaps  in  every  school  district  in  Minnesota,  it 
should,  especially  among  the  young,  stimulate  an  interest  in  the  study  of  plants. 
With  a  minimum  of  technicalities,  sentimentalities,  unavoidable  inaccuracies  or  cum- 
bersome details,  it  seeks  to  accomplish  the  following  ends: 

1.  The  plant  world  is  presented  as  an  assemblage  of  living  things. 

2.  The  different  kinds  of  plants  in  Minnesota,  from  the  lowest  to  the  highest, 
are  briefly  reviewed  in  their  natural  order. 

3.  Some  plant  structures  and  behaviors  are  elementarily  explained,  as  adapta- 
tions to  surrounding  nature. 

4.  Certain  plant  individuals  and  societies  are  brought  before  the  reader  as  hav- 
ing life  problems  of  their  own,  not  as  mere  material  for  economic,  anatomical  or 
classificatory  industry. 

In  short,  I  have  recognized  that  there  are  in  Minnesota  a  number  of  intelligent 
men  and  women,  boys  and  girls,  who  wish  to  know  more  about  plants,  and  in  the 
pages  of  this  book  I  have  sought  to  bring  together  what,  from  my  own  experience  as 
a  student  of  plants,  and  as  an  instructor  of  the  young,  seems  to  me  a  sufficiently 
adequate  and  compact  presentation  of  the  subject.  Errors  of  judgment  and  of  fact  no 
doubt  exist,  as  in  many  works  of  mere  human  construction.  I  hope  that  they  will 
not  prove  harmful.  In  some  matters,  indeed,  the  point  of  view  has  shifted  since  cer- 
tain chapters  were  in  type.  For  example,  experiments  recently  completed  by  the 
United  States  Department  of  Agriculture  tend  to  modify  the  German  and  Danish  ex- 


vi  Minnesota  Plant  Life. 

planations  of  bacterial  relation  to  dairy  industries  and  to  the  curing  of  tobacco.  Other 
new  facts  have  been  elicited  by  investigators  studying  the  red  and  purple  coloring 
substances  in  plants,  so  that,  if  prepared  to-dayt  various  chapters  would  undergo 
slight  alteration*  In  a  subject  developing  so  rapidly  as  is  modern  botany,  it  is  diffi- 
cult to  be  always  absolutely  abreast  of  the  current. 

A  large  number  of  the  illustrations  in  the  volume  are  from  photographs  of  Min- 
nesota vegetation,  some  of  them  made  by  myself,  or  under  my  direction,  others 
selected  from  the  collections  of  friends,  acquaintances  and  dealers.  Many  figures, 
too,  have  been  obtained  in  other  ways.  I  have  particularly  to  thank  Dr.  N,  L. 
Britton,  of  the  New  York  Botanic  Garden,  for  the  cuts  from  his  splendid  Illustrated 
Flora  of  North  America,  here  credited  to  Britton  and  Brown.  I  am  also  much  in- 
debted to  Professor  G.  F.  Atkinson,  of  Cornell  University,  for  permission  to  use  nu- 
merous engravings  from  his  excellent  text-book,  Elementary  ^Botany,  and  likewise 
express  my  thanks  to  the  United  States  Department  of  Agriculture,  to  Professor 
Francis  Ramaley,  of  the  University  of  Colorado,  Mr.  C.  G.  Lloyd,  of  Cincinnati,  the 
Botanical  Gazette,  Meehan  rs  Monthly,  Professor  L.  H.  Bailey,  of  Cornell  Univer- 
sity, Professor  B.  D.  Halsted,  of  Rutgers  College,  Professors  Hall  and  Appleby  and 
Instructors  Mackintosh,  Mills  and  "Wheeler,  of  the  University  of  Minnesota,  Professor 
Bruce  Fink,  of  Fayette  College,  the  late  Warren  W.  Pendergast,  and  several  others, 
all  of  whom  have  assisted  me  in  collecting  illustrations.  Tarn  also  greatly  obliged  to 
my  father,  Dr.  Geo.  McMillan,  for  much  valuable  assistance  with  the  proofs,  and  to 
Miss  Josephine  E.  Tilden  for  the  preparation  of  the  index. 

I  am  particularly  indebted  to  President  Cyrus  Northrop  for  suggestions  and 
assistance,  without  which,  in  all  probability,  this  volume  would  have  been  neither 
prepared  nor  published. 

Among  many  books  that  I  had  occasion  to  consult  during  the  preparation  of 
manuscript  the  Illustrated  Flora  of  Britton  and  Brown,  Sargent's  magnificent  Sileua, 
Kerner's  'Plant  Life,  "Warming's  Ecology,  Schimper's  'Plant  Geography,  Lafar's 
Technical  Mycology  and  Upham's  Catalogue  of  the  Minnesota  Flora,  deserve 
especial  mention.  Yet  I  should  not  give  the  impression  that  cMinnesota  Plant  Life 
is  wholly  a  product  of  the  study;  it  is  much  more  the  offspring  of  the  woods,  the 
prairies,  the  rivers  and  the  lakes.  In  every  part  of  the  state,  during  the  past  twelve 
years,  I  have  visited  them,  and  this  book,  with  whatever  merits  and  demerits  it  may 
have,  received  an  inspiration  from  such  excursions  among  the  plants  themselves. 

If,  by  the  distribution  of  this  volume  a  broader  knowledge,  a  deeper  interest,  a 
truer  appreciation  and  a  better  understanding  comes  to  those  in  whose  hands  its  pages 
open,  the  writer  will  feel  well  repaid  for  the  labor  of  preparation.  An  intelligent 
study  of  nature  is  one  of  the  foundation  stones  of  useful  citizenship. 

The  University  of  Minnesota, 
October  2,  1899. 


Table  of  Contents* 


PREFACE  ............................................................  v 

CHAPTER  I  ...........  Plants  in  their  Societies  ......................  I 

CHAPTER  II  ..........  Plant  Wanderings  and  Migrations  .............  18 

CHAPTER  III  .........  Slime-moulds  and  Blue-green  Algae  .........  ;  .  26 

CHAPTER  IV  .........  Bright-green    Algae  ...........................  33 

CHAPTER  V  ..........  Brown  Algae  and  Red  Algae  ..................  39 

CHAPTER  VI  .........  The  Lower  Sorts  of  Fungi  ...................  43 

CHAPTER  VII  ........  Smuts  and  Rusts  .............................  48 

CHAPTER  VIII  .......  Trembling  Fungi,  Club-fungi,  Shelf-fungi  and 

Mushrooms    ...............................  55 

CHAPTER  IX  .........  Carrion-fungi  and  Puff-balls  ...................  66 

CHAPTER  X  ..........  Yeasts,  Morels,  Cup-fungi  and  Truffles  ......  ."  .  72 

CHAPTER  XI  ..........  Blights,  Black-fungi  and  Root-fungi  .........  80 

CHAPTER  XII  ........  Lichens  and  Beetle-fungi  ......................  91 

CHAPTER  XIII  .......  Various  Kinds  of  Bacteria  ....................  101 

CHAPTER  XIV  .......  Mosses  and  Liverworts  as  Links  between  the 

Algae  and  Higher  Plants  ...................  122 

CHAPTER  XV  ........  Liverworts  of  Minnesota  ......................  132 

CHAPTER  XVI  .......  Mosses  of  Minnesota  .........................  144 

CHAPTER  XVII  ......  Christmas-green  Plants  or  Club-mosses  .......  156 

CHAPTER  XVIII  .....  Ferns  and  Water-ferns  ........................  161 

CHAPTER  XIX  .......  Scouring-rushes  and  Horse-tails  ...............  175 

CHAPTER  XX  ........  What  Seeds  Are  and  how  they  are  Produced.  .  .  180 

CHAPTER  XXI  .......  Ground-hemlocks  and  Various  Pines  ..........  185 

CHAPTER  XXII  ......  From  Cat-tails  to  Eel-grasses  .................  197 

CHAPTER  XXIII  .....  Grasses  and  Sedges  ...........................  204 


Vlll 


Minnesota  Plant  Life. 


CHAPTER  XXIV From  Callas  to  Water-star-grasses 217 

CHAPTER  XXV Rushes,  Lilies,  Blue  Flags  and  Orchids 224 

CHAPTER  X  XVI Poplars  and  Willows 233 

CHAPTER  XXVII From  Bayberries  to  Oaks,  Elms  and  Nettles..  .  243 

CHAPTER  XXVIII  . .  .  From  Sandalwoods  to  Buttercups 256 

CHAPTER  XXIX From  Barberries  to  Witch-hazels 274 

CHAPTER  XXX Roses,  Peas  and  the  Relatives 286 

CHAPTER  XXXI From  Geraniums  to  Maples  and  Touch-me-nots  305 

CHAPTER  XXXII From  Buckthorns  to  Prickly  Pears 319 

CHAPTER  XXXIII. ..  From  Leatherwoods  to  Dogwoods. 332 

CHAPTER  XXXIV  ...  High  Types  and  Low  Types  of  Flowers 343 

CHAPTER  XXXV  ....  From  Wintergreens  to  Chaffweeds. 350 

CHAPTER  XXXVI  . .  .  From  Ash  Trees  to  Verbenas 360 

CHAPTER  XXXVII .  .  From  Peppermints  to   Plantains 375 

CHAPTER  XXXVIII  .  From  Bedstraws  to  Lobelias 388 

CHAPTER  XXXIX.  ..  Dandelions,  Ragweeds  and  Thistles 

CHAPTER  XL Adaptations  of  Plants  to  their  Surroundings.. 

CHAPTER  XLI Hydrophytic    Plants 

CHAPTER  XLII Xerophytic   Plants 

CHAPTER  XLHI Halophytes  and  Mesophytes 473 

CHAPTER  XLIV Maintenance  of  the  Plant  Individual 483 

CHAPTER  XLV Maintenance  of  the  Plant  Species 509 


399 
417 

442 

463 


List  of  Plates. 


PLATE  I.  A  ravine  near  St.  Paul,  where  shade-loving  plants  make 
their  home.  From  a  photograph  by  Dr.  Francis 
Ramaley Frontispiece. 

PLATE  II.  In  the  black  oak  country.  Near  the  Chisago  lakes.  From 

a  photograph  by  Dr.  Francis  Ramaley 248 

PLATE  III.  Pond  with  lilies.  Ramsey  county.  Around  it  are  growing 
oaks,  willows,  sumacs  and  blue  flags,  milkweeds  and 
smartweeds.  From  a  photograph  by  Williams 312 

PLATE  IV.  Roadside  vegetation  near  St.  Paul.  The  most  conspicu- 
ous plants  are  hemp,  wormwood,  squirrel-tail  grass  and 
daisies.  From  a  photograph  by  Dr.  Francis  Ramaley.  . .  456 


Index  to  Illustrations* 


FIG.  i.  In  the  forest  district.  Growth  of  white  pines  and  spruces  upon 
a  rocky  island.  Steamboat  channel,  Lake  of  the  Woods. 
After  photograph  by  the  author  ............................  7 

FIG.  2.     Prairie  scene  on  the  Coteau.    Sunflowers  line  the  roadway  on 

either  side.    After  photograph  by  Mr.  R.  S.  Mackintosh  .....        9 

FIG.  3.    Roadside    vegetation.     Grasses    and   pulses.     An   elm   tree    in 

background.     Cedar  lake.    After  photograph  by  Williams...       10 

FIG.  4.  Spruces  forming  a  zone  around  a  peat-bog.  Farther  back  are 
tamaracks  and  pines.  The  shrub  in  the  foreground  is  the 
bog-willow,  while  the  flowers  are  those  of  an  orchid,  —  Pogo- 
nia.  Near  Grand  Rapids.  After  photograph  by  Mr.  Warren 
Pendergast  ................................................  1  1 

FIG.  5.  Zones  of  aquatic  vegetation.  In  the  center  pond-lilies;  at  the 
edge  smartweed;  farther  back  cat-tails,  blue  flags,  sweet  flags 
and  sedges;  still  farther  back  soft  turf  with  grass,  moss, 
sedge  and  milkweed.  After  photograph  by  Williams  ........  12 

FIG.  6.  Island  in  the  Mississippi  above  St.  Paul.  The  center  is  occu- 
pied by  elms  while  the  rim  is  fringed  with  willows.  An  ex- 
ample of  a  "minor  tension."  After  photograph  by  Professor 
W.  R.  Appleby  ............................................  14 

FIG.  7.  Lake  border  vegetation  of  cat-tails,  grasses,  reeds  and  sedges. 

Lake  of  the  Isles.  After  photograph  by  Williams  ...........  18 

FIG.  8.  Portion  of  a  board  which  had  been  standing  in  the  tank  shown 
in  Fig.  10.  It  is  encrusted  with  limestone  deposited  by  a 
colony  of  blue-green  algae.  After  photograph  by  Miss  Jos- 
ephine E.  Tilclen.  From  the  Botanical  Gazette  ...............  31 


xii  Minnesota  Plant  Life. 

FIG.  9.  Portion  of  a  pond-scum  thread,  showing  how  it  is  made  up  of 
transparent-walled  cells  with  a  coiled  green  ribbon  in  each, 
much  magnified.  After  Atkinson 34 

FIG.  10.  Patches  of  pond-scum  floating  in  a  tank.  A  lime-encrusting 
alga  grows  on  the  boards  up  to  high-water  mark.  Near 
Minneapolis.  After  photograph  by  Mr.  R.  W.  Squires 35 

FIG.  ii.  Patches  of  wheat-rust,  natural  size  and  enlarged.  The  red  rust 

stage.  After  Atkinson 51 

FIG.  12.  Patches  of  wheat-rust,  natural  size  and  enlarged.  The  black 

rust  stage.  After  Atkinson 51 

FIG.  13.  Wheat-rust  in  its  barberry-leaf  stage;  to  the  left  a  barberry 
leaf  with  diseased  spots;  in  the  middle,  a  single  spot  with 
cups;  to  the  right,  two  of  the  cups,  in  top  view  slightly  mag- 
nified. After  Atkinson 52 

FIG.  14.  Magnified  section  through  a  cluster-cup  of  the  wheat-rust  in  its 
barberry-leaf  stage.  Shows  chains  of  spore-cells.  The  large 
cells  at  the  sides  are  those  of  the  barberry  leaf  much  magni- 
fied. After  Atkinson 53 

FIG.  15.    Growth  of  club-fungi  on  decaying  wood.    After  Lloyd 56 

FIG.  16.  Shelf-fungus  growing  on  dead  stump  of  oak  tree.  After  pho- 
tograph by  Hibbard 57 

FIG.  17.    Upper  and  under  sides  of  mushroom-like  pore-fungus.    After 

Lloyd    59 

FIG.  18.  A  pore-fungus  lying  flat  upon  a  decaying  branch.  After  Lloyd  60 
FIG.  19.  Deadly  variety  of  mushroom.  After  Atkinson.  Bulletin  138, 

Cornell  Ag.  Exp.  Station.    This  is  sometimes  known  as  the 

"poison  cup" 61 

FIG.  20.  Under  side  of  two  mushroom-fruits.  After  Atkinson.  Bulletin 

138,  Cornell  Ag.  Exp.  Station 62 

FIG.  21.  Common  edible  mushroom.  After  Atkinson.  Bulletin  138, 

Cornell  Ag.  Exp.  Station 63 


Minnesota  Plant  Life.  xiii 

FIG.  22.  Development  of  mushroom-fruits  on  their  underground  vege- 
tative tract.  After  Atkinson.  Bulletin  138,  Cornell  Ag.  Exp. 

Station   64 

FIG.  23.    Warty  puff-ball.    After  Lloyd 68 

FIG.  24.    Tufted  puff-ball.    After  Lloyd 69 

FIG.  25.     Pocket-fungus    on    sand-cherry.     After    Bailey.      Bulletin    70, 

Cornell  Ag.  Exp.  Station 74 

FIG.  26.    A  morel  fruit-body.    After  Lloyd 75 

FIG.  27.     Cup-fungi  growing  on  decaying  twig.    After  Lloyd 76 

FIG.  28.    Leaf-spot  disease  caused  by  fungus.    After  Halsted 82 

FIG.  29.  Leaf-spot  fungus  growing  on  pear  leaves.  After  Duggar.  Bul- 
letin 145,  Cornell  Ag.  Exp.  Station 83 

FIG.  30.    Fungus  spot-disease  of  strawberry  leaf.    After  Bailey.    Bulletin 

79,  Cornell  Univ.  Ag.  Exp.  Station 84 

FIG.  31.  Fungus  spot-disease  on  leaf  of  false  Solomon's  seal.  After 

Halsted 85 

FIG.  32.  Fungus  spot-disease  on  pear.  After  Duggar.  Bulletin  145, 

Cornell  Ag.  Exp.  Station • 86 

FIG.  33.    Fungus  spot-disease  of  bean  pods.    After  Halsted 87 

FIG.  34.    Twig-fungus  on  currant  canes.    After  Durand.     Bulletin   125, 

Cornell  Exp.  Station 88 

FIG.  35.    Rock-lichens  growing  profusely  in  a  glacial  pot-hole.    Near 

Taylor's  Falls.    After  photograph  by  Mr.  E.  C.  Mills 92 

FIG.  36.  "Old  man's  beard."  A  lichen  growing  attached  to  the  twigs 
of  tamarack.  Lake  Superior,  north  shore.  Natural  size,  six 
inches  in  length.  After  photograph  by  Professor  Bruce  Fink  93, 

FIG.  37.  A  lichen  growing  upon  a  rock,  and  covered  with  the  charac- 
teristic saucer-shaped  fruits  of  its  fungus  component.  After 
Atkinson  95 


xiv  Minnesota  Plant  Life. 

FIG.  38.  A  tuft  of  "reindeer  moss."  Natural  size,  2.y2  feet  in  diameter. 
Age,  probably  over  one  hundred  years.  North  shore  of  Lake 
Superior.  After  photograph  by  Professor  Bruce  Fink 97 

FIG.  39.  A  male  moss  plant.  The  spermaries  are  produced  in  clusters 

at  the  end  of  the  stem.  After  Atkinson 125 

FIG.  40.  A  female  moss  plant.  The  egg-organs  are  inclosed  in  the  tuft 

of  leaves  at  the  tip  of  the  stem.  After  Atkinson 125 

FIG.  41.  The  club-shaped  spermary  of  a  moss,  much  magnified,  and  two 

sperni£tozoids,  very  highly  magnified.  After  Atkinson 126 

FIG.  42.  Tip  of  a  leafy  moss  plant,  sectioned  lengthwise  and  magnified. 
The  flask-shaped  egg-organs,  one  with  an  egg  in  place,  are 
shown.  These  bodies  are  barely  visible  to  the  naked  eye. 
After  Atkinson 127 

FIG.  43.  Mud-flat  liverwort,  showing  method  of  growth  and  branch- 
ing. After  Atkinson 132 

FIG.  44.  The  umbrella-liverwort;  showing  the  prostrate  vegetative 
body,  and  the  upright  branches  on  which  the  egg-organs  are 
borne,  and  where  later  the  capsular  plants  will  be  found 
perching.  After  Atkinson ^5 

FIG.  45.  Stem  of  the  umbrella-liverwort,  showing  the  little  cups  with 
bodies  inside,  which  are  employed  by  the  plant  for  purposes 
of  propagation.  After  Atkinson j^g 

FIG.  46.  Road  across  a  peat-bog;  tamaracks  and  birches  in  background. 
Near  Grand  Rapids.  After  photograph  by  Mr.  Warren  Pen- 
dergast I45 

FIG.  47.  Peat-moss  leafy-plants  with  capsular-plants  imbedded  at  the 

tips  of  short  leafless  erect  branches.  After  Atkinson 147 

FIG.  48.  A  moss  leafy-plant,  with  prostrate  propagative  branch  and 
erect  female  reproductive  branch.  On  the  latter  two  egg- 
organs  have  developed  their  eggs  into  capsular  plants,  one 
of  which  is  ejecting  spores.  The  two  round  bodies  are  spores 
much  magnified.  After  Atkinson.  .  153 


Minnesota  Plant  Life.  xv 

Fir,.  49.  Branch  of  a  club-moss  plant,  hearing  two  cones;  with  a  single 
leaf  of  the  cone,  showing  the  spore  case  and  one  of  the 

spores,  the  latter  much  magnified.    After  Atkinson 156 

FIG.  50.     Flat-branched  club-moss.    After  Britton  and  Brown 158 

FIG.  51.  Smaller  club-moss.  To  the  left  a  plant  with  three  cones,  next 
a  single  cone  dissected  to  show  the  spore  cases,  next  a  single 
large-spore-case  with  four  spores  revealed,  and  on  the  right 
a  small- spore-case  with  the  small  spores  sifting  out.  After 

Atkinson    159 

FIG.  52.    Adder's-tongue    fern.      After    E.     N.    Williams,    in    Meeharis 

Monthly   162 

FIG.  53.    Virginia  grape-fern.    After  Britton  and  Brown 163 

FIG.  54.     A  quillwort  plant.    After  Atkinson 164 

FIG.  55.     Clayton's,  or  interrupted  fern.    After  Britton  and  Brown 164 

FIG.  56.     Bed  of  ferns.     Sensitive  fern  in  middle  of  foreground.    After 

photograph  by   Williams 165 

FIG.  57.     Cliff-brake.    After  Britton  and  Brown 166 

FIG.  58.  The  interrupted  fern  (in  background)  and  shield-ferns  (in  fore- 
ground). After  photograph  by  Williams 167 

FIG.  59.     Four-leaved  water-fern.    After  Britton  and  Brown 168 

FIG.  60.  A  sexual  fern-plant  somewhat  magnified.  Its  natural  size  is 
about  a  quarter  of  an  inch  across.  The  round  bodies  are 
spermaries,  the  chimney-shaped  ones  are  egg-organs,  seen 

from  below.    After  Atkinson 168 

FIG.  61.  A  fern-plant  embryo  imbedded  in  the  enlarged  egg-organ, 
where  it  arose  by  segmentation  of  an  egg.  S,  tip  of  rudi- 
mentary stem ;  L,  tip  of  first  leaf;  R,  tip  of  primitive  rootlet; 

F,  nursing  foot.     Much  magnified.    After  Atkinson 169 

FIG.  62.  Portion  of  maiden-hair  fern  leaf,  showing  marginal  pockets, 
which  serve  to  protect  the  clusters  of  spore-cases  under  each 
Map.  After  Atkinson 170 


xvi  Minnesota  Plant  Life. 

FIG.  63.  A  patch  of  spore-cases  on  the  back  of  a  common  polypody- 
fern-leaf.  Magnified.  After  Atkinson 170 

FIG.  64.  Spore-cases  of  the  common  fern,  much  magnified,  showing 
how  the  spring  back  reverts  and  then  snaps  shut  again, 
throwing  the  spores  as  from  a  sling.  After  Atkinson 171 

FIG.  65.  A  walking-fern  climbing  down  a  hillside.  Buds  form  at  the 
very  tips  of  the  slender  leaves  and  grow  into  new  plants. 
After  Atkinson 1 72 

FIG.  66.  Maiden-hair  ferns  and  lady  ferns.  After  photograph  by  Wil- 
liams    173 

FIG.  67.  A  fruiting  stem  of  the  horse-tail.  The  shield-shaped  spore- 
bearing  leaves  are  aggregated  in  a  cone.  After  Atkinson.. .  .  176 

FIG.  68.  Scouring-rush  spores;  to  the  left  a  spore  with  appendages 
curled  up,  in  moist  air;  to  the  right  a  spore  with  appendages 
extended,  in  dry  air.  After  Atkinson 177 

FIG.  69.  Diagram  of  an  ovary,  with  one  seed-rudiment,  in  a  higher 
seed-plant,  s,  the  stigma,  where  two  pollen-spores  have 
germinated;  o,  wall  of  ovary;  f,  stalk  of  ovule;  ai  and  ii, 
rudimentary  seed-coats;  n,  spore-case,  with  single  large 
spore,  which  has  germinated  to  produce  the  reduced  female 
plant;  k,  the  egg;  e,  the  body  which  forms  the  albumen;  b, 
other  cells  of  the  female.  The  male  plant  is  shown  as  a  tubu- 
lar thread  growing  towards  the  egg.  After  Atkinson 181 

FIG.  70.  White  pines  on  the  rocks  at  Taylor's  Falls.  After  photograph 

by  Williams 187 

FIG.  71.    Jack  pine.    After  Britton  and  Brown 188 

FIG.  72.  Rock-vegetation  near  Duluth.  White  pines,  white  cedars  and 

junipers.  After  photograph  by  Williams 189 

FIG.  73.  Tamarack  swamp  with  sedge  border.  After  photograph  by 

Williams 191 

FIG.  74.  Red  cedars  on  the  banks  of  a  Minnesota  lake.  After  photo- 
graph by  Williams 193 


Minnesota  Plant  Life.  xvii 

FIG.  75.  Rock  on  the  St.  Croix  river,  near  Taylor's  Falls.  Shows  zonal 
distribution  of  trees.  White  pines  stand  on  top  of  the  rock, 
and  birches  and  poplars  on  the  sides.  After  photograph  by 
Mr.  H.  C.  Cutler 195 

FIG.  76.    Bur-reed.    After  Britton  and  Brown 198 

FIG.  77.  Lakeside  vegetation.  Just  off  shore  is  a  growth  of  the  floating 
pondweed,  then  of  arrowheads,  while  farther  out  are  reeds 

and  rushes.    After  photograph  by  Williams 199 

FIG.  78.     Clasping-leaved  pondweed.    After  Britton  and  Brown. .......     200 

FIG.  79.  Evening  scene  in  Minnesota.  Arrowheads,  bulrushes  and  wil- 
lows in  foreground.  After  photograph  by  Williams 201 

FIG.  80.    Arrowhead.    After  Britton  and  Brown 202 

FIG.  81.    Eel-grass.    After  Britton  and  Brown 202 

FIG.  82.    Wild  rice  and  pond  lilies.    After  photograph  by  Williams 204 

FIG.  83.    Beard-grass.    After  Britton  and  Brown 205 

FIG.  84.     Barnyard  grass.    After  Britton  and  Brown 205 

FIG.  85.     Minnesota  Muhlenberg  grass.    After  Britton  and  Brown 206 

FIG.  86.     Beckman  grass.    After  Britton  and  Brown 206 

FIG.  87.    Indian  corn  in  the  shock.    After  photograph  by  Williams 207 

FIG.  88.    Wild  rice  in  a  Minnesota  lake.    After  photograph  by  Williams    208 

FIG.  89.    Wild  rice.    After  Britton  and  Brown 209 

FIG.  90.     Kalm's  brome-grass.    After  Britton  and  Brown 209 

FIG.  91.    A    cluster    of   sedge-flowers    (Carex-type),    a    single    pistillate 
flower  with  one  fruit  rudiment,  and  a  staminate  flower  with 

three  stamens.    After  Atkinson 210 

FIG.  92.     Cyperus-sedge.    After  Britton  and  Brown 211 

FIG.  93.     Cotton-grasses  growing  in  a  bed  of  peat-moss.     Near  Grand 

Rapids.    After  photograph  by  Mr.  Warren  Pendergast 212 

FIG.  94.    Lake   border   vegetation.     Bulrushes   and   reed-grasses.    After 

photograph  by  Williams 213 


xviii  Minnesota  Plant  Life. 

FIG.  95.     Bulrush-sedge.    After  Britton  and  Brown 214 

FIG.  96.    Carex-sedge.    After  Britton  and  Brown 215 

FIG.  97.  A  skunk-cabbage  in  early  spring,  before  the  leaves  have  un- 
folded. The  purple  hood  covering  the  flower  cluster  is 

shown  on  one  side.    After  Atkinson 218 

FIG.  98.    Sedges  and  rushes.    After  photograph  by  Williams 224 

FIG.  99.    Dog's-tooth  violet  in  flower.    After  Atkinson 225 

FIG.  100.   Clintonia.    After  Britton  and  Brown 225 

FIG.  101.  Blue  flags.    After  photograph  by  Williams 226 

FIG.  102.  Stream-side  vegetation.  Blue  flags  in  foreground.  After  pho- 
tograph by  Williams 227 

FIG.  103.  Yellow  lady-slipper.  After  photograph  by  Mr.  R.  S.  Mackin- 
tosh    229 

FIG.  104.  Wild  orchis.    After  Britton  and  Brown 230 

FIG.  105.  Cottonwoods  on  the  Minnesota.  After  photograph  by  Wil- 
liams    235 

FIG.  106.   Poplar  vegetation  of  burnt  district.     Near  Rat  Portage,  Ont. 

After  photograph  by  the  author 237 

FIG.  107.   Cottonwood.    After  Britton  and  Brown 238 

FIG.  108.   Peach-leafed  willows  on  shore  of  stream.    After  photograph  by 

Williams  239 

FIG.  109.  Clusters  of  willow  flowers;  on  the  left  the  pistillate  flowers 
and  on  the  right  the  staminate.  Each  pistillate  flower  con- 
sists principally  of  a  single  fruit-rudiment,  and  each  staminate 
flower  of  two,  or  sometimes  a  larger  number  of  stamens. 

After  Atkinson 240 

FIG.  no.  Beach  vegetation,  Garden  Island,  Lake  of  the  Woods.  The 
long-leafed  willow  forms  the  outer  zone,  and  the  black  willow 

the  inner.    After  photograph  by  the  author 241 

FIG.  in.  Hickory  trees.  Lake  Minnetonka.  After  photograph  by  Wil- 
liams    244 


Minnesota  Plant  Life.  xix 

FIG.  112.  Ironwoods  and  oaks.  The  smaller  trees  are  ironwoods  and 
hop-hornbeams.  Lake  Calhoun.  After  photograph  by  Hib- 

bard   245 

FIG.  113.  The  paper  or  canoe  birch.    After  photograph  by  Williams.  ..  .     247 
FIG.  114.  An  Indian  encampment,  Lake  of  the  Woods.    The  vegetation 
is  principally  the  canoe  birch,  and  the  canoes  and  tepees  illus- 
trate the  uses  to  which  birch-bark  is  put  by  the  aborigines. 
After   photograph     by    Wright.     From   Minnesota   Botanical 

Studies   248 

FIG.  115.  An  oak  twig  with  leaves  and  both  sorts  of  flowers.  The  one 
with  three  prongs  is  the  pistillate  flower;  the  other,  with  five 
stamens,  is  the  staminate.  The  staminate  flowers  grow  in 

drooping  clusters.    After  Atkinson 249 

FIG.  116.  Oaks  and  blue  flags.    A  marshy  place  in  the  oak-woods.    After 

photograph  by  Williams 250 

FIG.  117.    American  elm.    After  Britton  and  Brown 251 

FIG.  118.  American  elm.  Lake  Minnetonka.  After  photograph  by  Wil- 
liams   252 

FIG.  119.  Roadside   vegetation   of    nettles   and   vines.     Winter   aspect. 

After  photograph  by  Williams 254 

FIG.  120.  Glasswort.    After  Britton  and  Brown 259 

FIG.  121.  Pokeweed.    After  Chesnut.    F.  B.  86,  U.  S.  Dept.  Ag 260 

FIG.  122.  Carpetweed.    After  Britton  and  Brown 261 

FIG.  123.  Spring-beauty  in  flower.    After  Atkinson 262 

FIG.  124.  Water-shield.    After  Britton  and  Brown 264 

FIG.  125.  Water-lilies.    After  photograph  by  Williams 265 

FIG.  126.  Marsh-marigold  or  cowslip.    After  Britton  and  Brown 268 

FIG.  127.  False  rue-anemone  growing  in  pots.  University  plant  house. 
After  photograph  by  Dr.  D.  T.  MacDougal.  From  Minne- 
sota Botanical  Studies 270 

FIG.  128.  White  water-buttercup.    After  Britton  and  Brown 271 


xx  Minnesota  Plant  Life. 

FIG.  129.  Early  meadow-rue.    After  Britton  and  Brown 272 

FIG.  130.  May-apple,  or  mandrake,  in  flower.    After  Atkinson 275 

FIG.  131.  Clammy-weed.    After  Britton  and  Brown 276 

FIG.  132.  Blood-root.    After  Britton  and  Brown 276 

FIG.  133.  Water-cress.    After  Britton  and  Brown 277 

FIG.  134.   Pitcher-plant.    After  Britton  and  Brown 278 

FIG.  135.  Sundew.    After  Britton  and  Brown 280 

FIG.  136.  River-weed.    After  Britton  and  Brown 281 

FIG.  137.  American  alum-root.    After  Britton  and  Brown 282 

FIG.  138.  Marsh  Parnassia.    After  Britton  and  Brown 283 

FIG.  139.  Hawthorn.    After  Britton  and  Brown 287 

FIG.  140.  Apple-blossoms.    After  photograph  by  Williams 288 

FIG.  141.   Marsh  fivefinger.    After  Britton  and  Brown 289 

FIG.  142.  Roses.    After  photograph  by  Williams 291 

FIG.  143.  Sand-cherry  in  fruit.    After  Bailey.     Bulletin  70,  Cornell  Ag. 

Exp.  Station 292 

FIG.  144.  A   cluster   of  choke-cherry  flowers   and   a   single   flower   dis- 
sected.   After  Atkinson 293 

FIG.  145.  Kentucky  coffee-tree.    After  Britton  and  Brown 296 

FIG.  146.  Wild  lupine.    After  Britton  and  Brown 298 

FIG.  147.  Sweet-clover  bushes.    After  photograph  by  Williams 299 

FIG.  148.  White  clover.    After  photograph  by  Williams 300 

FIG.  149.  Tick-trefoil.    After  Britton  and  Brown 303 

FIG.  150.  Sumac  bushes,  with  golden-rods  in  foreground  and  maples  in 

background.    After  photograph  by  Williams 309 

FIG.  151.   Poison-sumac.    After  Chesnut.    F.  B.  86,  U.  S.  Dept.  Ag 310 

FIG.  152.  Poison-ivy.    After  .Chesnut    F.  B.  86,  U.  S.  Dept.  Ag 311 

FIG.  153.  Leaves  and  flowers  of  the  sugar-maple.    After  Atkinson 314 

FIG.  154.  A   grove   of   sugar-maples.      Near   Lake    Minnetonka.     After 

photograph  by  Mr.  E.  C.  Mills 315 


Minnesota  Plant  Life.  xxi 

FIG.  155.   Moosewood  maple.    After  Britton  and  Brown 316 

FIG.  156.  Touch-me-not.    After  Britton  and  Brown 317 

FIG.  157.  Tree  covered  by  grape-vine.    After  photograph  by  Williams. .  320 
FIG.  158.  Virginia  creeper  on  tree  trunks.    After  Schneck  in  Meehan's 

Monthly   322 

FIG.  159.  Basswood  trees.    Shore  of  Lake  Calhoun.    After  photograph 

by  Hibbard 324 

FIG.  160.   Beach  heather.    After  Britton  and  Brown 327 

FIG.  161.  Sweet  white  violet.    After  Britton  and  Brown 328 

FIG.  162.  Western  prickly-pear  cactus.    After  Britton  and  Brown 330 

FIG.  163.  Ginseng.    After  Britton  and  Brown 337 

FIG.  164.  Water-parsnip.    After  Britton  and  Brown 338 

FIG.  165.  Wild  parsley.    After  photograph  by  Williams 339 

FIG.  1 66.  Water-hemlock.    After  Chesnut.    F.  B.  86,  U.  S.  Dept.  Ag..  .  340 

FIG.  167.  Dwarf  cornel.    After  Britton  and  Brown 341 

FIG.  168.  Wintergreen  plant  in  flower.    After  Atkinson 351 

FIG.  169.   Kalmia  flowers.    After  Atkinson 354 

FIG.  170.   Moss-plant.    After  Britton  and  Brown 355 

FIG.  171.   Small  cranberry.    After  Britton  and  Brown 357 

FIG.  172.   Yellow  gentian.    After  Britton  and  Brown 362 

FIG.  173.  Swamp  milkweed.    After  Britton  and  Brown 365 

FIG.  174.  Brookside  vegetation.    Milkweeds  in  foreground.    After  pho- 
tograph by  Williams 366 

FIG.  175.   Dodder  in  flower;    the  parasite  is  seen  to  be  clutching  tightly 

the  stem  of  its  host  plant.    After  Atkinson 368 

FIG.  176.  Virginia  water-leaf.    After  Britton  and  Brown 37° 

FIG.  177.   Blue  verbena.    After  Britton  and  Brown 373 

FIG.  178.  Wild  mint.    After  Britton  and  Brown 375 

FIG.  179.   Clump   of   horse-mint    (in   middle   of   picture).    After   photo- 
graph by  Williams 376 


xxii  Minnesota  Plant  Life. 

FIG.  180.   Horse-mint.    After  Britton  and  Brown 377 

FIG.  181.  View  in  Minnesota  lake  district.  Shows  in  center  two  mullein 
plants  in  characteristic  positions.  After  photograph  by  Wil- 
liam s  380 

FIG.  182.   Monkey  flower.    After  Britton  and  Brown 381 

FIG.  183.  Lousewort.    After  Britton  and  Brown 382 

FIG.  184.   Bladderwort.    After  Britton  and  Brown 383 

FIG.  185.  Cancerroot.    After  Jellett  in  Median's  Monthly 385 

FIG.  186.   Rugel's  plantain.    After  Britton  and  Brown 386 

FIG.  187.   Bedstraw.    After  Britton  and  Brown 389 

FIG.  188.   Partridgeberry.    After  Britton  and  Brown 389 

FIG.  189.   High  bush  cranberry.    After  Britton  and  Brown 390 

FIG.  190.  Snowberry.    After  Britton  and  Brown 392 

FIG.  191.  Blue-bells.    After  Britton  and  Brown 395 

FIG.  192.   Blue  lobelia.    After  Britton  and  Brown 396 

FIG.  193.  Chrysanthemum  in  flower.  After  Miller.  Bulletin  147,  Cor- 
nell Ag.  Exp.  Station 400 

FIG.  194.  Dandelions  in  flower.    Lake  Calhoun.    After  photograph  by 

Hibbard   401 

FIG.  195.   Dandelions  in  fruit.    After  photograph  by  Williams 402 

FIG.  196.  Wild  lettuce,  a  compass-plant;  the  fruits  stand  in  heads,  and 
each  fruit  is  provided  with  a  parachute  of  bristles.  After 

Atkinson    403 

FIG.  197.  Rattlesnake-root.    After  Britton  and  Brown 404 

FIG.  198.  Cocklebur.    After  Britton  and  Brown 404 

FIG.  199.  Ragweed.    After  Britton  and  Brown 405 

FIG.  200.  Autumnal  vegetation  of  marsh  border.    Thoroughwort  or  joe- 

pye  weed.    After  photograph  by  Williams 406 

FIG.  201.   Boneset  or  thoroughwort.    After  Britton  and  Brown 407 

FIG.  202.  Blazing-star.    After  Britton  and  Brown 407 


Minnesota  Plant  Life.  xxiii 

FIG.  203.  Autumnal  composite  vegetation.  In  foreground  golden-rods, 
sunflowers  and  asters;  in  background,  on  brow  of  cliff, 
wormwood  or  sage-brush.  After  photograph  by  Williams..  .  408 

FIG.  204.  Early  golden-rod.    After  Britton  and  Brown 409 

FIG.  205.  Asters  a'nd  golden-rod.  Banks  of  the  Mississippi.  After  pho- 
tograph by  Williams 410 

FIG.  206.   Rosinweed  compass-plant.    After  Britton  and  Brown 411 

FIG.  207.   Cone-flowers.    After  photograph  by  Williams 412 

FIG.  208.   Prairie  cone-flower.    After  Britton  and  Brown 413 

FIG.  209.  Water  bur-marigold.    After  Britton  and  Brown 414 

FIG.  210.   Corn-flower.    After  Britton  and  Brown 414 

FIG.  211.  Bur  oak  and  bracken  fern.  Illustrates  relation  between  strength 
of  stem  and  the  weight  to  be  borne.  After  photograph  by 

Hibbard    419 

FIG.  212.  Willows   and   bulrushes.     The    latter   are   typical    surf-plants. 

After  photograph  by  Williams 421 

FIG.  213.   Elm  tree  growing  in  the  open.    Light  is  received  on  all  sides. 

After  photograph  by  Williams 429 

FIG.  214.  Two-leafed  wood-lilies.  These  plants  have  the  broad  leaves  of 
shade  plants  and  the  white,  conspicuous  flowers.  After  pho- 
tograph by  Hibbard 430 

FIG.  215.  Jack-in-the-pulpit.  A  shade  plant.  After  photograph  by  Hib- 
bard   431 

FIG.  216.   Leaves  of  the   sensitive  fern,   a   shade-loving  variety.     After 

photograph  by  Hibbard 432 

FIG.  217.  The  Virginia  creeper  on  the  walls  of  the  old  round  tower, 
Fort  Snelling.  This  plant  does  not  turn  towards  the  sun,  but 
clings  to  the  shaded  wall.  After  photograph  by  Williams.  . .  .  433 
FIG.  218.  "Gallery  woods,"  near  Minnesota  Falls,  valley  of  the  Minne- 
sota, in  the  prairie  district.  Dependence  of  trees  upon  mois- 
ture is  illustrated  by  their  grouping  in  declivities.  After  pho- 
tograph by  Professor  R.  D.  Irving 434 


xxiv  Minnesota  Plant  Life. 

FIG.  219.  Dandelion  fruiting  in  shady  spot.  Shows  the  slender  stems 
and  erect  root-leaves  of  the  shady  habitat,  and  fruits  adapted 
for  wind  distribution.  After  photograph  by  Hibbard 441 

FIG.  220.  Vegetation  of  ravine.  The  home  of  mosses  and  liverworts. 
The  plants  in  front  are  touch-me-nots.  After  photograph  by 
Williams  447 

FIG.  221.  Stream-side  vegetation.  Ironweeds,  thoroughwort,  mullein, 
sedge,  speedwell  and  shrubbery.  Hydrophytic  vegetation  in 
water's  edge.  After  photograph  by  Williams 448 

FIG.  222.  Birch  trees  along  a  lake  shore.  Bar  vegetation  in  background. 

After  photograph  by  Williams 449 

FIG.  223.  Trees  along  a  river  bank.  Soft  maple  and  cottonwood.  Min- 
nesota river.  After  photograph  by  Williams 452 

FIG.  224.  Marshy  place  at  the  edge  of  a  wood.  After  photograph  by 

Murdock  454 

FIG.  225.  Ferns  in  tamarack  swamp,  Lake  Calhoun.  After  photograph 

by  Hibbard 455 

FIG.  226.  Swamp  saxifrages.  The  large  root-leaves  are  adapted  to  the 
shade  of  the  swamp.  The  whole  plant  is  hairy.  Tamarack 
swamp,  Lake  Harriet.  After  photograph  by  Hibbard 456 

FIG.  227.  A  marsh-loving  sedge,  showing  fruit  clusters.  After  photo- 
graph by  Hibbard 458 

FIG.  228.  A  pitcher  plant  in  flower;  tamarack  swamp.  The  leaves  are 

converted  into  insect-traps.  After  photograph  by  Hibbard. .  .  461 

FIG.  229.  Rock  vegetation,  Lake  of  the  Woods,  near  Keewatin,  Ontario. 
Junipers,  bellworts,  pines,  ferns,  poplars  and  grasses  predom- 
inate. After  photograph  by  Wright 466 

FIG.  230.  Growth  of  hardwood  trees  upon  a  rocky  island.  Northwest 

angle,  Lake  of  the  Woods.  After  photograph  by  the  author.  .  468 

FIG.  231.  Vegetation  of  sand  dunes,  Isle  aux  Sables,  Lake  of  the 
Woods.  In  the  foreground  is  the  sand  cherry  and  scrub 
poplar,  in  the  center  a  juniper  bush  and  in  the  background 
plums.  After  photograph  by  the  author 470 


Minnesota  Plant  Life.  xxv 

FIG.  232.  The  valley  of  the  Minnesota  river  in  the  prairie  district.  Abun- 
dant grass  vegetation.  After  photograph  by  Professor  R.  D. 
Irving  471 

FIG.  233.  Cottonwood  trees  on  the  Minnesota  river.  After  photograph 

by  Williams 474 

FIG.  234.  A  Minnesota  meadow  bordered  by  shrubbery  and  deciduous 

forest.  After  photograph  by  Mr.  W.  A.  Wheeler 475 

FIG.  235.  Roadside  vegetation  in  summer.  After  photograph  by  Wil- 
liams    477 

FIG.  236.  Roadside  vegetation  in  winter,  St.  Anthony  Park.  Oaks,  sun- 
flowers and  goldenrods.  After  photograph  by  Williams 477 

FIG.  237.  Autumnal  underbrush,  Mississippi  river,  between  Minneapolis 
and  St.  Paul.  Golden  rods,  asters  and  sumac.  After  photo- 
graph by  Williams 478 

FIG.  238.  Neglected  corner  in  the  Minneapolis  manufacturing  district. 

Weeds  and  shrubbery.  After  photograph  by  Williams 479 

FIG.  239.  Modern  hardwood  forest  of  the  St.  Croix  valley,  near  Osceola. 

After  photograph  by  Professor  W.  R.  Appleby 480 

FIG.  240.  View  of  Fort  Snelling,  showing  midsummer  vegetation.  After 

photograph  by  Williams 481 


Chapter  I. 

Plants  in  their   Societies* 


Purpose  of  this  book.  In  the  pages  of  this  book  I  hope 
to  give  the  reader  an  idea  of  the  diversified  plant  life  which 
occupies  the  air,  the  soil  and  the  waters  of  Minnesota.  First 
of  all,  it  must  be  remembered  that  plants  although  passive 
creatures  are  quite  as  truly  living  beings  as  are  the  more  active 
animals.  Just  as  men  and  women,  either  themselves  or  their 
ancestors,  have  entered  the  state  from  some  other  region,  so 
also  have  plants,  according  to  the  nature  of  each,  found  their 
way  and  selected  their  abodes.  It  is  no  easy  problem  to  de- 
termine why  some  family  has  chosen  one  village  rather  than 
another.  This  may  have  been  from  causes  which  are  too  subtle 
or  too  remote  for  analysis,  but  it  is  recognized  that  people  have 
not  come  to  make  their  homes  without  some  reason  which 
seemed  sufficient  to  them  or  to  their  forefathers.  So,  too, 
there  is  always  some  reason  for  the  appearance  at  a  particular 
spot  of  one  kind  of  plant  rather  than  another,  and  it  is  possible 
ir  i  general  way  to  explain  the  vegetation  of  the  hills  and 
meadows  of  the  state. 

Minnesota  geography.  A  glance  at  the  map  will  show  that 
the  State  of  Minnesota  lies  between  the  43rd  and  49th  paral- 
lels of  north  latitude  and  between  the  8gth  and  97th  meri- 
dians west,  and  that  it  is  centrally  located  in  the  North  Ameri- 
can continent.  Within  its  domain  rises  the  Mississippi  and 
by  this  great  river  the  surplus  rain-fall  of  the  state  is  in  large 
measure  carried  away  to  the  Gulf  of  Mexico.  The  northwest- 
ern portion,  by  the  Red  river  and  its  tributaries,  is  drained 
through  Lake  Winnipeg  into  Hudson  bay,  while  a  few  streams 
flow  in  the  valley  of  the  St.  Lawrence  to  the  Atlantic  ocean. 
Minnesota,  therefore,  is  not  only  geographically  but  hydro- 
graphically  central.  Hence  it  might  be  supposed  that  its  plants 


2  Minnesota  Plant  Life. 

would  have  immigrated  equally  from  all  directions.  Such,  how- 
ever, is  bv  no  means  the  fact  and  it  is  needful  to  inquire  further 
into  the  conditions  which  regulate  plant  distribution  before 
the  true  situation  can  be  understood. 

Minnesota  climate.  Connected  with  the  geographical  posi- 
tion of  the  state,  and  to  a  very  great  degree  dependent  upon 
it,  is  that  combination  of  average  winds,  average  temperature, 
average  precipitation  of  moisture,  and  average  illumination 
by  the  sun  to  which  is  given  the  general  name  of  climate.  Min- 
nesota enjoys  what  is  known  as  a  mid-continental  climate, 
characterized  by  warmth  in  the  summer  and  cold  in  the  winter. 
There  are  no  prevailing  winds  from  years  end  to  year's  end 
as  there  are  at  some  places  by  the  sea.  The  sun  never  shines 
with  equatorial  directness,  nor  are  there  ever  weeks  or  months 
of  twilight,  or  of  darkness,  as  in  the  regions  of  the  poles.  There 
are  no  great  mountain  ranges  to  cool  the  clouds  as  they  move 
across  the  sky  and  to  force  them  to  yield  their  moisture  in  the 
eternal  snows;  and  during  the  year  there  may  always  be  ex- 
pected an  average  rain-fall  of  about  twenty-five  inches.  Through 
the  spring  and  summer  there  is  always  a  rise  in  temperature  to 
stimulate  growth,  but  there  is  never  that  fervent,  damp  heat 
which  favors  the  rank  and  luxuriant  vegetation  of  the  tropics. 
Consequently  there  are  to  be  found  in  Minnesota,  plants  adapted 
to  the  rhythm  of  the  seasons,  to  the  oblique  illumination  of  the 
sun,  to  the  average  moisture  of  the  air  and  of  the  soil,  and  to 
the  winds  which  sometimes  sweep  over  the  prairies  with  an 
almost  resistless  force. 

As  an  illustration  of  the  adaptation  of  plants  to  seasonal 
rhythm  may  be  mentioned  the  autumnal  habit  of  most  trees  in 
Minnesota  of  shedding  their  leaves.  Indeed,  this  is  so  common 
a  fact  of  experience  that  it  is  scarcely  realized  to  be  a  definite 
reaction  of  the  plant  to  its  environment.  Yet  leaves  do  not  fall 
merely  because  the  nights  are  growing  cold,  but  because  there 
is  formed  at  the  base  of  each  leaf-stalk  a  little  layer  of  cork 
which,  when  complete,  cuts  the  leaf  from  the  twig  as  if  by  a  pair 
of  shears.  Certainly  such  is  not  everywhere  a  necessary  habit, 
for  it  is  known  that  in  the  tropics  many  trees  do  not  lose  their 
leaves  each  year,  but  retain  them  for  varying  periods  of  time 
until  their  usefulness  is  past — a  character  shared  also  by  some 


Minnesota  Plant  Life.  3 

trees  of  temperate  regions.  Apparently,  then,  the  habit  of 
rejecting  leaves  that  would  be  killed  by  the  winter's  cold  and 
would  become  burdensome  another  summer  may  be  directly 
connected  with  the  geographical  position  of  the  state. 

Again,  trees  with  enormous,  delicate  leaves  like  those  of  many 
palms  or  bananas,  are  not  found  upon  the  prairies  of  the  Red 
river,  because,  clearly,  if  trees  with  such  thin,  large  leaves  were 
exposed  to  the  wind  they  would  be  blown  to  pieces  and  their 
life  would  be  destroyed.  Large  delicate-leaved  forms  are  more 
characteristic  of  regions  where  the  wind  is  slight  or  where  it  is 
broken  by  masses  of  surrounding  vegetation. 

Furthermore,  in  a  state  so  well  watered  as  Minnesota  there 
is  no  development  of  those  curious  desert  types  which  are  seen 
in  Arizona,  in  the  Sahara,  or  in  the  arid  regions  of  South  Africa 
and  Australia;  for  where  it  is  arid  those  plants  only  can  grow 
that  by  structure  and  habits  are  fitted  to  utilize  the  relatively 
small  quantities  of  moisture.  The  strange  columnar  cacti  of 
the  Gila,  standing  leafless  and  rigid — vegetable  pillars  of  the 
desert — would  be  out  of  place  wherever  the  rain-fall  permits  the 
production  of  ordinary  leaves  and  branches.  Thus  in  survey- 
ing the  vegetation  of  the  world  one  is  impressed  with  the  influ- 
ence of  climate  upon  the  plant  population  of  every  district. 

The  physical  history  of  Minnesota.  A  knowledge  of  its 
geography  and  climate  does  not,  however,  afford  all  the  data 
for  comprehending  the  vegetation  of  any  region,  since  it  is  not 
alone  the  climate  of  to-day,  but  even  more  strongly  the  climate 
and  other  conditions  of  the  past,  that  are  reflected  in  the  forms 
and  structures  of  the  plants.  Therefore,  a  knowledge  also  of 
the  geological  history  of  the  state  and  of  its  various  soils  is 
essential  to  an  understanding  of  its  vegetation.  There  is  strong 
reason  to  suppose  that  about  ten  thousand  years  ago  much  of 
the  surface  of  North  America  was  covered  by  a  thick  sheet  of 
ice  which  advanced  slowly  from  the  north  and  later  as  slowly 
retreated.  The  period  of  ice-advance  is  known  to  geologists  as 
the  glacial  period,  and  throughout  Minnesota  are  to  be  found 
the  traces  of  glacial  action.  The  clays,  pebbles  and  bowlders  so 
abundant  throughout  the  state  are  believed  to  have  been  depos- 
ited either  upon  the  front  of  a  glacial  mass,  or  underneath,  or 
from  the  waters  caused  by  its  melting.  When  such  a  move- 


4  Minnesota  Plant  Life, 

ment  of  ice  took  place  there  must  have  been  a  great  modifica- 
tion of  drainage  conditions  over  all  the  invaded  district.  Streams 
were  dammed,  hills  were  levelled,  valleys  were  filled,  lake  bot- 
toms were  hollowed  out  or  covered  with  confused  masses  of 
rocks  and  clay — ground  into  pow^der  by  the  powerful  action  of 
the  ice,  continuing,  as  it  did,  through  more  than  a  thousand 
years.  It  is  clear,  too,  that  the  ancient  vegetation  must  have 
been  almost  wholly  swept  away  by  this  invasion  from  the  Arctic 
zone.  It  is  true  that  plants  are  sometimes  found  growing  close 
to  the  edge  of  glaciers  in  the  Alps,  in  Greenland  and  in  Alaska. 
Sometimes  even  masses  of  soil  are  so  borne  upon  the  surface  of 
the  glacier  that  plants  of  hardy  habit  may  continue  their  exist- 
ence there.  Yet,  with  a  due  regard  to  these  well-known  facts, 
it  is  not  conceivable  that  for  so  long  a  period  of  rigorous  cold 
the  old  pre-glacial  plant-population  of  the  state  could  have  held 
its  ground.  It  must  be  supposed,  rather,  that  as  the  glacier 
steadily  advanced  from  the  north,  year  after  year  plants  flung 
their  seeds  into  air-currents  moving  southward  or  attached  them 
to  the  fur  of  animals  seeking  a  warmer  clime  and  thus  gradu- 
ally season  by  season  themselves  migrated  toward  the  south. 
Evidently  those  plants  provided  with  seeds,  buoyant,  winged, 
barbed  or  hooked  were  best  fitted  by  such  contrivances  to  leave 
the  snows  and  ice  of  a  thousand  years,  while  the  plants  with 
smooth  and  heavy  seeds  either  migrated  more  leisurely  and 
more  sparingly  or  were  quite  extinguished  by  the  cold. 

When  the  glacial  period  came  finally  to  an  end  and  the  ice- 
sheet  moved  north  beyond  the  confines  of  the  state,  there 
opened  to  the  immigrants  from  the  south  a  new  Minnesota. 
Great  lakes  formed  by  the  waters  of  the  melting  ice  now  lay 
where  before  there  was  land.  Rivers  were  flowing  in  new  direc- 
tions and  were  carving  for  themselves  new  gorges  through  the 
rocks.  A  fertile  soil  was  deposited  upon  the  hill-sides — not, 
indeed,  a  rich  leaf-mould,  but  capable  of  supporting  many  kinds 
of  plants.  Into  this  land  of  promise  the  southern  plants  began 
to  come.  Winds  from  the  south,  animals  ranging  toward  the 
north  and  water-fowl  in  their  annual  migrations,  brought  back 
in  some  instances  no  doubt  the  very  same  varieties  which  hun- 
dreds of  years  earlier  had  fled  before  the  ice,  and  in  others,  new 
kinds  born  and  bred  in  the  south  and  seeking  new  homes  where 


Minnesota  Plant  Life.  5 

they  might  obtain  a  foothold  for  themselves  and  their  descend- 
ants. When  one  contemplates  for  a  moment  this  epitome  of 
plant-wanderings  he  is  impressed  by  its  similarity  to  the  history 
of  his  own  race.  It  is  known  how  peoples  have  moved  from 
one  country  to  another,  not  usually  en  masse  but  individually, 
quite  as  did  the  plants  and  under  very  much  the  same  impelling 
forces.  For  it  is  those  plants  which  were  able  to  leave  the  region 
of  increasing  cold  that  later  continued  their  kind  under  more 
favorable  circumstances,  as  it  is  also  the  hardy  race  of  men  who 
migrate  from  the  worn  out  farm,  or  congested  city  to  some 
new  country  in  which  they  may  find  prosperity  and  happiness 
for  themselves  and  for  their  children. 

Laws  of  plant  distribution.  There  are,  then,  three  paths 
along  which  to  seek  the  general  laws  of  plant  distribution.  First, 
as  regards  an  area,  one  must  inquire  what  is  its  geographical 
position?  second,  what  is  its  climate?  third,  what  is  its  soil 
and  physical  history?  The  answers  to  these  three  questions  ex- 
plain in  large  degree  what  must  be  the  plant  population  of  that 
area.  With  respect  to  the  vegetation  of  Minnesota  the  most 
impressive  fact  is  that  it  is  an  immigrant  vegetation.  It  mani- 
fests the  characters  of  a  new  community  quite  as  truly  as  does 
the  American  Republic,  in  its  social  and  political  organization, 
the  characters  of  a  new  country.  This  can  be  illustrated  clearly 
if  one  compare  the  Minnesota  forest  with  the  ancient  forest  of 
the  tropics  in  India,  in  Venezuela,  or  about  the  sources  of  the 
Nile.  When  one  enters  the  dark  solitudes  of  an  equatorial  for- 
est his  first  thought  is,  from  the  sounds  that  reach  his  ears,  that 
the  life  of  the  forest  must  be  above  his  head.  Few  animals  are 
seen,  almost  no  insects  and  scarcely  a  green  leaf  or  plant  upon 
the  forest-floor,  but  there,  rather,  are  dead  and  decaying  trunks 
of  trees  which  have  fallen  and  massive  columns  of  trees  that  are 
standing,  while  arching  overhead  are  interlaced  branches  that 
intercept  the  light  and  make  the  scene  like  that  in  some  dim 
cathedral.  But  if  from  a  balloon  one  could  look  down  upon  the 
immemorial  crowns  he  would  see  spread  out  beneath  him  a 
world  alive  with  birds  and  insects,  brilliant  with  flowers  and  rich 
with  the  verdure  of  vines  and  air-plants.  It  would  be  much  as 
if  the  tree-tops  had  taken  the  place  of  the  turf  and  shrubbery  of 
more  northern  climes.  Many  orchids  and  other  plants  of  that 


6  Minnesota  Plant  Life. 

nature  would  be  seen  perched  upon  the  branches,  dangling  their 
roots  into  the  damp  air  below;  climbing  and  twining  plants 
would  be  abundant  and  especially  would  there  be  observed  a 
much  greater  variety  over  a  particular  area  than  could  be 
expected  in  temperate  regions.  This  peculiarity  of  the  tropical 
forest,  this  exuberant  development  of  tree-top  life  is  a  natural 
result  of  age.  It  is  because  the  forest  has  been  standing  for 
countless  centuries,  unmodified  by  changes  of  climate,  unin- 
vaded  by  glacial  sheets,  that  it  includes  so  many  different  kinds 
of  individuals.  For  the  same  reason  there  have  arisen  depen- 
dencies between  different  varieties  of  plants,  and  some  have 
learned  to  perch  themselves  upon  the  branches  of  others  or  have 
entwined  themselves  around  the  stems  of  their  neighbors.  Just 
so,  in  an  old  societv  like  that  of  India  or  wherever  there  is  not 
the  democracy  and  equality  which  exists  under  a  newer  social 
order,  is  caste  developed.  People  are  born  to  be  dependent  and 
it  is  fore-ordained  in  the  social  system  that  they  and  their  de- 
scendants shall  not  rise  above  this  position. 

In  the  forests  of  Minnesota  all  is  very  different.  When  one 
enters  the  pine-woods  of  the  north,  or  the  elm  and  maple-woods 
of  the  south,  he  is  not  impressed  with  the  silence  and  solitude 
of  the  forest-floor,  nor  does  he  discover  that  the  tree-tops  have 
become  a  special  soil  for  the  development  of  peculiar  plants. 
Perching  plants  are  rare ;  vines  and  lianas  do  not  form  so  large 
a  proportion  of  the  total  population.  There  is  nearly  always  a 
well-developed  underbrush,  and  many  sorts  of  little  heaths, 
asters,  gentians  and  golden-rods  display  their  flowers  and  ripen 
their  fruits  under  the  shadow  of  the  trees.  They  are  not  com- 
pelled by  the  umbrageous  growth  of  larger  plants  to  climb  the 
trunks  or  hang  themselves  upon  the  topmost  branches  in  order 
to  obtain  their  share  of  sunlight  and  of  rain.  Nor  is  the  number 
of  kinds  in  an  acre  nearly  so  great  as  in  the  tropics,  for  there 
has  not  yet  ensued  that  long  period  of  competition  which,  in  the 
tropical  forest,  has  reduced  what  might  once  have  been  social 
clumps  of  trees  to  the  lone  survivors  of  to-day. 

Forest  and  prairie.  There  are  two  principal  vegetation- 
regions  in  Minnesota,  the  forest  and  the  prairie.  The  forest 
occupies  the  northern  portion  of  the  state  extending  south  to 


Minnesota  Plant  Life.  j 

the  valley  of  the  Minnesota  river.  The  prairie  comprises  the 
southern  portion  of  the  state  and  a  strip  along  the  western 
boundary  in  the  valley  of  the  Red  river  of  the  North.  These 
two  regions,  so  different  in  their  appearance,  are  inhabited  by 
plants  which  are  not  altogether  dissimilar  to  each  other.  Most 
of  the  plants  at  home  on  the  prairie  are  not  entirely  absent  from 
the  forest,  while  the  greater  number  of  forest  plants  may  be 
encountered,  possibly  not  so  abundantly,  but  at  least  casually, 
on  the  prairie.  The  difference  between  the  two  regions  does 


FIG.  1. — In  the  forest  district.     Growth  of  white  pines  and  spruces  upon  a  rocky  island. 
Steamboat  channel,  I,ake  of  the  Woods.     After  photograph  by  the  author. 

not  lie  in  differences  in  the  kinds  of  plants  so  much  as  it  does  in 
the  different  character  of  the  dominant  plants.  Among  the  pines 
and  spruces  of  the  forest  occur  many  of  the  grasses,  vetches 
and  asters  of  the  prairie.  Along  the  borders  of  prairie  sloughs 
and  streams  there  will  be  growing  the  same  varieties  of  arrow- 
heads, milkweeds  and  willow-herbs  that  form  a  characteristic 
vegetation  in  similar  places  in  the  forest.  But  the  dominant 
plants  of  the  forest  are  trees,  lifting  up  their  erect,  perennial 
stems,  struggling  with  each  other  for  light  and  air  and  giving  to 
the  whole  formation  an  upright  effect,  while  the  prairies  are 


8  Minnesota  Plant  Life. 

dominated  by  grasses  with  prostrate  underground  stems  woven 
together  into  a  solid  and  matted  turf,  thrusting  into  the  air  only 
their  side-branches  and  thus  giving  to  the  whole  a  flat  and  level 
character.  It  is  not  very  well  known  precisely  why  the  prairie 
type  of  vegetation  has  established  itself  over  such  large  areas  of 
the  world.  Some  have  attributed  it  to  fires,  others  have  thought 
that  climate  and  soil  are  responsible  for  the  difference  between 
prairie  and  forest.  Perhaps  all  that  need  be  said  is  that  there 
are  these  two  principal  methods  of  developing  plant-stems. 
When  the  dominant  plants  of  an  area  are  such  as  have  acquired 
the  habit  of  trying  to  avoid  each  other's  shade  by  elongation  of 
their  stems,  that  region  is  a  forest.  When,  on  the  other  hand, 
an  area  is  occupied  by  plants  that  have  learned  to  elbow  each 
other  beneath  the  surface  of  the  soil,  that  region  is  a  prairie. 
It  is  a  mistake  to  suppose  that  the  lofty  tree  is  in  every  sense 
stronger  than  the  modest  grass,  for  the  two  have  simply  devised 
different  means  of  accomplishing  the  same  result.  A  prime 
necessity  of  most  plants  is  sunlight,  since  without  it  they  are 
unable  to  construct  their  food  from  the  gases  of  the  atmosphere 
and  the  water  of  their  sap.  Therefore,  they  must  have  light, 
and  to  obtain  it  they  adopt  instinctively  the  methods  of  growth 
which  will  enable  them  to  do  their  own  life-work  regardless  of 
their  neighbors.  The  pine  tree  may  be  described  as  a  plant 
which  for  ages  has  been  solving  the  problem  of  better  illumina- 
tion by  a  progressive  increase  in  height.  The  grass,  by  copious 
ramification  of  a  protected  underground  stem  upon  which  lat- 
eral leaf-bearing  branches  are  produced,  in  its  way  strives  to 
obtain  illumination,  nutriment  and  persistence. 

Another  difference  which  exists  between  the  forest  and  prairie 
of  Minnesota  is  in  the  direction  from  which  the  plants  have 
come.  The  forest  is,  in  large  part,  composed,  so  far  as  its  domi- 
nant plants  are  concerned,  of  northern  forms,  while  the  prairie 
is  inhabited  rather  by  immigrants  from  the  south.  So  on  a 
map  illustrating  plant  distribution  in  the  northern  hemisphere 
it  will  be  found  that  the  prairies  in  Europe,  in  Asia  and  in 
America  lie  south  of  a  forest  belt.  It  is  true  that  in  the  tropics 
around  the  world  a  forest  region  exists,  broken  only  by  deserts 
like  those  of  the  Sahara,  or  northern  Australia ;  but  in  regions 
beyond  the  tropics  it  would  seem  that  in  both  hemispheres  there 


Minnesota  Plant  Life.  g 

are  intermediate  forest  zones  between  the  prairies  of  temperate 
regions  and  the  tundras  about  the  poles. 

Minnesota  is  situated  between  the  forest  and  prairie  regions 
of  the  North  American  continent  and  includes  a  representation 
of  each.  A  careful  study  of  the  populations  in  these  regions 
will  show  that  each  is  striving  to  extend  itself;  thus  wherever  a 
stream  flows  from  the  forests  of  the  north  down  through  the 
prairies  of  the  south,  forest  plants  advance  along  the  banks  and 
reach  more  southern  latitudes.  In  Minnesota  the  pine  trees 
that  in  the  north  form  so  characteristic  a  growth  are  found  in 
isolated  patches,  fewer  in  numbers,  down  the  Mississippi — even 


FIG.  2. — Prairie  scene  on  the  Coteau.     Sunflowers  line  the  roadway  on  either  side.     After 
photograph  by  Mr.  R.  S.  Macintosh. 

beyond  the  confines  of  the  state,  for  the  white  pine  exists  upon 
the  Mississippi  bluffs  in  Iowa.  Similarly,  along  the  open  which 
a  river  produces,  there  is  chance  for  southern  winds  to  distribute 
the  seeds  of  prairie  plants,  and  characteristic  vegetation  of  the 
prairie,  such  as  sunflowers  and  golden-rods,  has  pushed  its  way 
up  into  the  forest,  leaving  the  larger  streams  along  their  tribu- 
taries, and  finding  a  path  even  into  depths  of  the  pine-woods 
where  the  soil  is  favorable.  It  would  be  a  great  mistake  to 
count  plants  quiet,  unenterprising  creatures,  not  alert  to  make 
use  of  every  opportunity  for  growth  and  development.  The 
forest  must  rather  be  regarded  as  composed  of  plants  eager  to 
compete  with  those  of  the  prairie  upon  their  own  ground,  and 
equally  must  the  prairie  plants  be  regarded  as  ambitious  on  their 


10 


Minnesota  Plant  Life. 


part  to  try  conclusions  with  those  of  the  forest,  if  they  obtain  an 
opportunity  to  penetrate  between  the  interstices  of  the  more 
northern  erect  formation. 

Plant  populations,  then,  in  the  two  great  vegetation  regions 
of  the  state,  are  in  a  state  of  tension,  and  the  line  between  them 
is  necessarily  slowly  shifting  and  irregular.  Some  little  change 
in  the  topography,  some  slight  modification  of  the  drainage, 
the  drying  up  of  a  lake  or  the  erosion  of  a  deeper  gorge  by  a 
stream,  may  give  an  opportunity  for  one  formation  or  the  other 
to  extend  its  limits  at  the  expense  of  its  neighbor.  This  gen- 
eral state  of  tension  exists  not  only  between  the  forest  and  the 


FIG.  3. — Roadside  vegetation.     Grasses  and  pulses.    An  elm  tree  in  background. 
Cedar  lake.     After  photograph  by  Williams. 

prairie,  but  also  between  plants  on  the  tops  of  hills  and  those 
at  the  base,  between  plants  in  the  center  of  swamps  and  those 
at  the  circumference,  or  between  plants  at  the  edge  of  a  lake  or 
stream  and  those  farther  inland. 

Plant  zones.  The  result  of  such  competition  is  seen  in  the 
pretty  general  appearance  of  plant  zones  wherever  the  topog- 
raphy permits  them  to  be  developed.  A  simple  and  well-known 
example  of  this  tendency  of  plants  to  grow  in  zones  or  lines 
may  be  seen  along  any  road,  path,  ditch  or  trail  in  the  state. 
It  is  well  known  that  certain  kinds  of  plants  particularly  select 
the  road-side  as  a  favorite  place  for  growth.  Such  are  usually 


Minnesota  Plant  Life. 


1 1 


robust,  enterprising  plants  of  modern  structure,  and  the  pick  of 
the  whole  world  for  growing  ability — for  nowhere  is  there  so 
great  a  proportion  of  what  are  called  weeds  and  introduced 
plants  as  beside  a  road.  There  one  finds  the  knot-grasses,  rag- 
weeds, thistles,  cockscomb-grasses  and  other  imported  species, 
many  of  them  belonging  to  types  which  by  sheer  vegetable 
enterprise  and  ability  have  found  their  way  with  man  around 
the  whole  northern  hemisphere,  and  some  of  them  are  common 
even  to  Australia  and  Africa  as  well.  As  might  be  expected 


FIG.  4. — Spruces  forming  a  zone  around  a  peat-bog.  Farther  back  are  tamaracks  and  pines. 
The  shrub  in  the  foreground  is  the  bog-willow,  while  the  flowers  are  those  of  an  orchid, — 
Pogonia.  Near  Grand  Rapids.  After  photograph  by  Mr. Warren  Pendergast. 

from  their  distribution  along  paths  or  other  works  made  by 
man,  they  have  been  assisted  in  their  wanderings  by  human 
agencies  rather  than  by  the  ministrations  of  the  winds,  the 
water-fowl  or  the  beasts  of  the  field.  Such  plants  appear  also 
in  door-yards,  in  neglected  meadows,  in  pastures,  along  railway 
lines  and  in  short  wherever  man  has  gone. 

Another  kind  of  zonal  distribution,  not  influenced  by  human 
agencies,  may  be  seen  around  the  lakes  of  the  state,  especially 
where  beaches  have  been  formed.  Here  special  beach-rows  of 


12 


Minnesota  Plant  Life. 


plants  will  be  found,  consisting  among  others  of  certain  sand- 
loving  grasses,  cockleburrs,  pinks  and  fumitories,  and  clearly 
distinct  from  the  plants  farther  back  upon  the  shore.  Nor  will 
these  plants  develop  so  vigorously  under  any  other  conditions. 
Again  in  the  swamp  region  of  the  north,  where  a  peat-bog  is 
slowly  filling  with  moss  and  encroaching  upon  the  forest,  beau- 
tiful illustrations  of  this  zonal  arrangement  can  be  observed 
with  the  tamarack  and  spruce  trees  becoming  gradually  smaller 
and  smaller  toward  the  center  of  the  bog.  In  meadows,  too, 


FIG.  5. — Zones  of  aquatic  vegetation.  In  the  center  pond-lilies;  at  the  edge  smartweed;  far- 
ther back  cat-tails,  blue  flags,  sweet  flags,  and  sedges;  still  farther  back  soft  turf  with 
grass,  moss,  sedge  and  milkweed.  After  photograph  by  Williams. 

formed  by  the  drying-up  of  lakes,  are  sometimes  found  en- 
croachments of  the  meadow  plants  upon  such  knolls  as  were 
originally  islands  surrounded  by  water.  The  meadow,  as  it 
were,  washes  up  upon  the  knoll  and  upon  the  banks  of  the  old 
lake,  so  that  mingled  with  the  dogwoods,  willows  and  other 
shrubs  of  the  knoll  or  bank  one  will  observe  the  grasses  and 
sedges  of  the  meadow. 

Zonal  distribution  is  a  characteristic  arrangement  not  only  of 
land,  but  also  of  water  plants,  and  as  one  pushes  his  canoe  from 
the  shore  of  a  Minnesota  lake  he  will  doubtless  find  that  he 


Minnesota  Plant  Life.  i  3 

passes  over  distinct  zones  of  aquatic  vegetation.  First,  there 
will  be  the  sedges  at  the  water's  edge,  then  the  reed-grasses,  or 
wild  rice  in  a  little  deeper  water,  then  the  bulrushes  with  their 
cylindrical,  leafless  stems  rising  from  submerged  rootstocks 
below,  and  exposing  as  small  a  surface  as  possible  to  the  action 
of  the  surf.  Next  will  come  the  pond-lilies  and  water-lilies,  the 
water-shields,  and  sometimes  the  lotus  with  its  circular  leaves 
rising  from  or  floating  upon  the  water  and  presenting  every- 
where their  arched  margins  to  the  waves.  Then  come  the  pond- 
weeds  and  milfoils  with  their  stems  and  submerged  leaves 
ascending  through  the  water  but  not  reaching  the  surface,  and 
finally  the  bass-weeds  with  their  lime-encrusted  stems  and 
leaves  lying  upon  the  bottom  at  a  depth  of  from  ten  to  fifteen 
feet.  Whether  one  climbs  a  hill,  rows  out  into  a  lake,  walks 
from  the  margin  of  a  stream  back  to  the  prairie  or  the  woods; 
whether  one  steps  from  his  house  and  across  the  road  into  a 
field,  or  strolls  from  a  meadow  up  to  a  wooded  bank,  he  will 
find  that  he  is  traversing  zones  of  vegetation.  The  occasion  for 
such  a  distribution  of  plants  in  zones  is  to  be  sought  generally 
in  the  topography  of  the  region,  and  where  there  is  great  irregu- 
larity in  the  topography  there  is  irregularity  in  the  zones,  while 
sometimes  over  a  level  no  zones  appear.  Sometimes,  also, 
where  the  topography  is  favorable  to  the  development  of  plant 
zones  special  conditions  of  distribution  serve  to  obliterate  them 
or  prevent  their  occurrence. 

The  same  general  causes  which  tend  to  separate  the  forest 
from  the  prairie,  defining  their  limits,  are  seen  to  mark  also  the 
boundary  between  one  portion  of  the  forest  and  another.  Just 
as  the  great  prairie  group  of  plants  strives  as  a  whole  to  en- 
croach upon  the  forest,  so  the  plants  at  the  base  of  a  knoll  strive 
to  climb  it  and  establish  themselves  over  its  surface,  and  mean- 
while quite  as  vigorously  the  plants  on  the  knoll  attempt  to 
make  their  way  into  the  gullies  and  sloughs.  The  plant  on 
drier  soil  may  be  regarded  as  always  endeavoring  to  accommo- 
date itself  to  moister  soil,  and  that  on  moist  soil  as  always  strug- 
gling to  gain  a  foothold  where  the  moisture  is  not  so  great. 
So  there  are  often  seen  at  the  margin  of  ponds  the  pond-lilies 
emerging  as  far  as  they  are  able  upon  the  mud,  exerting  them- 
selves to  the  full  limit  of  their  structural  qualities  to  maintain 


14  Minnesota  Plant  Life. 

a  terrestrial  life,  and  in  the  same  pond  may  be  found  land-plants 
pushing  down  to  the  very  water's  edge  or  beyond  it  until  they 
can  go  no  farther  because  of  the  limitations  of  their  structure. 

The  tension  between  the  forest  and  prairie,  because  it  extends 
so  widely,  may  be  called  a  continental  tension.  The  other  ten- 
sions, between  knolls  and  ravines,  between  banks  and  meadows, 
between  beaches  and  pond  edges,  may  be  called  minor  tensions, 
but  the  law  of  the  two  cannot  be  very  different.  Indeed,  there 
may  be  gained  a  fair  idea  of  the  fundamental  difference  between 
prairie  and  forest  by  observation  of  an  area  so  limited  as  a  road- 


FIG.  6.— Island  in  the  Mississippi  above  St.  Paul.  The  center  is  occupied  by  elms  while  the 
rim  is  fringed  with  willows.  An  example  of  a  "minor  tension."  After  photograph  by 
Professor  W.  R.  Appleby. 

side  or  path.  The  principal  difference  between  the  two  is  the 
duration  of  the  causes  at  work.  Between  the  prairie  and  the 
forest  the  tension  has  been  in  existence  possibly  for  thousands 
of  years,  while  between  the  knoll  and  the  ravine  possibly  for  but 
a  few  decades  or  centuries.  As  a  result  there  have  come  to 
exist  in  the  old  warring  formations  structural  peculiarities  char- 
acteristic of  each,  so  that,  to  the  eye  of  the  observer,  they  pre- 
sent very  different  appearances.  Where  the  struggle  is  of  more 
recent  origin  and  of  more  limited  extent  the  differences  are  not 
so  great  and,  therefore,  not  so  evident. 

Forests  of  Minnesota  and  of  the  world.  We  cannot  well 
consider  forest  as  it  exists  in  Minnesota  apart  from  the  general 
forest  which  covers  the  northern  part  of  the  continent.  From 


Minnesota  Plant  Life.  15 

the  plant's  point  of  view,  Minnesota  is  not  a  province,  for,  to 
the  plant,  political  boundaries  as  established  by  man,  have  slight 
significance.  Nor  does  the  prairie,  which  occupies  the  south- 
ern part  of  the  state,  exist  as  a  special  Minnesota  prairie. 
Rather  is  it  the  northeastern  extension  of  the  great  plains  which 
occupy  the  whole  central  area  of  the  continent  from  the  foothills 
of  the  Rockies  back  to  the  forests  of  Kentucky,  Tennessee,  Indi- 
ana and  Wisconsin.  The  question  then  arises  how  did  the  for- 
ests come  to  consist  of  the  plants  which  dominate  them,  and 
how  did  the  prairie  come  to  have  its  particular  inhabitants 
rather  than  others? 

If  a  census  be  taken  of  all  the  kinds  of  plants  in  the  forests 
of  North  America  and  be  compared  with  a  similar  census  taken 
in  the  forests  of  Europe  and  Siberia  there  will  be  perceived  a 
great  similarity  between  the  plants  of  the  two  regions.  But  if 
in  like  manner  the  plants  of  the  prairies  of  the  United  States 
be  compared  with  those  growing  upon  the  steppes  of  Russia 
and  Siberia  it  will  be  discovered  that  the  similarity  is  not  by  any 
means  so  great.  A  very  much  larger  number  of  plants  are 
common  to  the  forest  districts  of  Europe,  Asia  and  North 
America  than  are  common  to  the  steppes  and  prairies  of  the  two 
hemispheres.  Yet,  in  this  latter  instance,  there  are  many 
groups  which  are  similar  and  not  a  few  identical  species.  Sup- 
pose, further,  that  the  forests  of  the  northern  hemsiphere,  of 
which  the  Minnesota  forest  is  but  a  portion,  be  compared  with 
the  deciduous  forests  of  the  southern  hemisphere,  including 
those  of  the  Transvaal  Republic,  Chili  and  the  Argentine,  New 
Zealand  and  Tasmania,  it  would  be  noticed  that  almost  no  com- 
mon species,  and  but  few  common  groups  of  species  can  be 
found.  Or  if  the  pampas  of  the  Argentine  be  compared  with 
the  prairies  of  the  United  States,  again  would  it  be  discovered 
that  the  common  species  are  exceedingly  scarce. 

It  would  seem,  then,  that  the  greatest  differences  which  exist 
between  plant  populations  of  the  world  are  between  those  of 
the  north  temperate  and  the  south  temperate  regions.  The 
occasion  of  this  will  be  understood  if  it  be  remembered  for  a 
moment  what  are  the  opportunities  for  the  expansion  of  plant- 
life  in  the  tropics  and  under  the  equator.  There  for  countless 
thousands  of  years  plants  have  been  developing  and  competing 


1 6  Minnesota  Plant  Life. 

with  one  another  amid  favorable  conditions  of  temperature, 
moisture  and  illumination.  The  equatorial  region  of  the  world 
is  at  once  the  cradle  and  the  crucible  of  plant-life.  In  that  tre- 
mendous struggle  for  existence  many  of  the  modern  improve- 
ments and  refinements  in  plant  structure  began  to  originate. 
During  the  centuries,  forms  unfavorable  were  eliminated  and 
destroyed,  leaving  the  stronger  in  a  condition  to  migrate  north 
or  south  as  rapidly  as  they  accommodated  themselves  to  the 
increasing  obliqueness  of  the  sun.  Evidently,  then,  the  great- 
est differences  should  be  expected  not  between  the  plants  of 
North  America  and  Europe,  both  of  them  tenanted  by  north- 
bound immigrants  from  the  equatorial  region,  nor  even  between 
the  north  temperate  regions  and  the  tropics,  since  the  plants  in 
the  former  are  but  the  traveled  relatives  of  those  at  home  in  the 
latter  region.  But  the  greatest  difference  should  be  expected 
to  exist,  as  it  does,  between  those  plants  which  have  left  the 
tropics  and  have  slowly  made  their  way,  changing  their  form 
and  habits  as  they  wandered,  some  to  the  far  north  and  others 
to  the  south. 

North  American  flora.  If  the  North  American  continent 
were  quite  flat,  without  differences  in  elevation  above  the  sea, 
and  were  connected  with  the  tropics  by  a  continuous  stretch  of 
land,  it  could  be  imagined  that  the  forest  region  might  have 
extended  directly  across  the  northern  half  of  the  continent. 
It  is,  however,  not  such  a  level  plain,  for  two  great  mountain 
ranges  run  from  north  to  south  and  the  continent  is  connected 
with  the  tropics  by  a  narrow  isthmus,  so  that  there  are  factors 
which  prevent  an  even  division  of  forest  and  prairie.  Mountain 
ranges  extending  from  north  to  south  are  not,  as  mountain 
ranges  extending  from  east  to  west  would  be,  barriers  against 
plant  distribution  from  the  tropics  toward  the  poles.  This  is 
the  reason  why  North  America  has  what  the  botanists  call  a 
"richer  flora"  than  Europe  and  Asia.  In  the  Old  World  the 
principal  mountain  ranges,  such  as  the  Pyrenees,  the  Alps,  the 
Appenines,  the  Carpathians,  the  Caucasus  and  the  Himalayas 
are  transverse,  extending  in  a  generally  east-and-west  direction. 
For  this  reason  when  the  glacial  period  came  on,  unfortunate 
European  or  Asiatic  plants  as  they  migrated  south,  found  them- 
selves compelled  to  climb  some  mountain  range  in  order  to 


Minnesota  Plant  Life.  17 

make  their  escape  to  the  temperate  climate  beyond  the  influ- 
ence of  the  ice,  and  under  these  conditions  most  of  them  must 
have  perished  as  wretchedly  as  did  so  many  of  the  troops  of 
Hannibal  when  they  crossed  the  Alps.  Moreover,  when  the  gla- 
cial period  came  to  an  end  in  Europe  and  Asia  it  was  difficult 
for  plants  to  return  over  the  mountain-passes,  and  as  a  result, 
these  continents  are  tenanted  by  a  less  diversified  vegetation 
than  that  of  North  America. 

The  longitudinal  mountain  ranges  of  the  New  World  have 
rather  aided  the  movements  of  plants  than  hindered  them,  for 
they  have  assisted  northern  plants  to  find  their  way  along  high 
altitudes  to  constantly  lower  latitudes,  while  at  the  various  stages 
of  their  journey  such  plants  have  enjoyed  the  opportunity  of 
climbing  down  the  mountain  sides  and  out  upon  the  plains,  if 
they  were  able  to  accommodate  themselves  to  the  higher  tem- 
perature. This  movement  has  taken  place  not  only  on  the 
western  side  of  the  continent,  but  also  along  the  Alleghenies. 
Yet  owing  to  the  greater  height  of  the  western  range  it  is  found 
that  northern  genera  of  plants  like  some  of  the  roses  and  willows 
have  developed  more  abundantly  toward  the  southwest  than 
toward  the  southeast,  simply  because  they  have  followed  an 
easier  path  along  the  cool  high  ridges  of  the  Rockies  than  along 
the  warmer,  lower  Appalachian  range.  By  these  two  mountain 
ranges,  lying  one  to  the  east  and  the  other  to  the  west  of  Minne- 
sota, some  slight  influence  has  no  doubt  been  exerted  upon 
plant  migration,  both  in  the  prairie  and  in  the  forest  region  of 
the  state.  But  this  effect  must  have  been  stronger  in  the  prairie 
region ;  for  the  forest  plants  from  the  east  and  north  could  enter 
as  easily  from  the  north  and  would  not  need  to  depend  upon 
any  lateral  movement.  From  the  west,  however,  where  the 
plains  rise  gently  to  the  mountains,  many  plants  which  had 
found  an  asylum  on  the  sides  of  peaks  and  escarpments  must 
have,  in  the  last  ten  thousand  years,  slowly  crept  down  into  the 
plains  and  there  developed  habits  and  structures  which  persist 
to  this  day. 

3 


Chapter  II. 

Plant  Wanderings  and  Migrations. 

*T 

Habits  of  birds  and  animals.  The  habits  of  birds  and  ani- 
mals are  of  much  importance  in  any  study  of  plant  distribu- 
tion ;  for  the  plant,  but  rarely  provided  with  independent  meth- 
ods of  locomotion,  is  forced  to  depend  upon  other  agencies  for 
dissemination.  To  the  waterfowl  especially,  with  their  well- 


FIG.  7.—  I^ake  border  vegetation  of  cat-tails,  grasses,  reeds  and  sedges, 
After  photograph  by  Williams. 


the  Isles. 


known  habit  of  flying  south  in  the  autumn  and  north  in  the 
spring,  do  many  plants  owe  the  widening  of  their  range.  Their 
seeds  are  ripened  and  fall  upon  the  mud  at  the  border  of  some 
lake  or  pond  where  they  are  picked  up  on  the  feet  or  plumage 
of  migrant  birds  and  are  carried  hundreds  of  miles  north  or 
south  of  the  point  where  they  were  produced.  That  is  one  rea- 


Minnesota  Plant  Life.  19 

son  why  throughout  Minnesota  the  lake-shore  vegetation  is  so 
homogeneous.  Every  bay  is  visited  at  some  time  during  the 
year  by  wild  fowl  and  in  the  mud  on  their  feet  they  carry  about 
the  seeds  of  a  variety  of  plants.  It  is  therefore,  those  water- 
edge  plants  which  have  seeds  not  too  large  to  be  thus  trans- 
ported that  are  the  more  widely  distributed.  Especially  if  the 
seed  is  of  a  kind  attractive  to  the  bird  is  it  likely  to  be  removed. 
Thus  ducks,  though  they  eat  hundreds  of  thousands  of  young 
wild-rice  plants  encased  in  their  seed-coats,  nevertheless  from 
their  very  habit  of  using  these  plants  for  food  distribute  them 
more  widely  than  if  they  were  not  thus  agreeable  to  their  taste. 

Migrating  animals,  like  the  bison  which  once  roamed  in  enor- 
mous herds  over  the  whole  prairie  region,  must  have  picked  up 
in  their  fur,  as  they  wallowed  in  the  sand  or  on  the  banks  of 
streams,  countless  seeds  of  a  great  variety  of  plants  and  carried 
them  to  all  parts  of  their  range.  In  this  way,  plants  having 
seeds  provided  with  attachment-prongs,  like  the  tick-trefoils, 
beggars'-lice,  burdocks  and  cockleburrs  must  have  obtained 
through  the  agency  of  animals  far  greater  opportunities  for 
travel  than  were  enjoyed  by  species  the  seeds  or  fruits  of  which 
were  hard  and  smooth. 

The  fancy  of  animals  and  birds  for  certain  sleeping  places 
has  also  influenced  plant  distribution,  and  their  habits  of  wan- 
dering in  the  woods  and  by  the  water  have  been  utilized  by  cer- 
tain kinds  of  plants,  and  some  remarkable  adaptations  exist, 
such  as  the  curious  explosive  seed-pods  of  the  touch-me-not. 
This  common  plant,  when  brushed  against,  explodes  its  fruits, 
throwing  out  the  seeds  where  they  may  be  caught  in  the  fur  of 
a  passing  animal  and  carried  away.  Certain  exotic  gourd-plants 
too,  have  explosive  fruits  which  when  agitated  by  a  slight 
touch  shoot  out  the  seeds  and  these,  provided  with  a  viscid 
membrane,  readily  adhere  to  the  passing  bird  or  animal.  Other 
plants  have  their  seeds  enclosed  in  edible  areas,  as  for  example 
the  gooseberries,  currants,  apples,  peaches,  raspberries,  junipers 
and  a  host  of  others.  In  such  fruits  the  seeds  are  themselves 
protected  by  hard  coats  which  resist  the  digestive  processes  of 
the  animal  or  bird  and  they  can  thus  pass  through  its  body  with- 
out injury.  Sometimes  the  instincts  of  animals  benefit  the 
plant,  as  when  a  squirrel  carries  off  an  acorn  and  buries  it  from 


2o  Minnesota  Plant  Life, 

some  dim  notion  of  secretiveness  or  possibly  of  providence. 
On  account  of  the  rhythm  of  the  seasons  in  Minnesota  the 
principal  migrations  of  birds  and  land  animals  have  not  been 
from  east  to  west  but  from  north  to  south,  and  the  principal 
tension-line  runs  in  general  from  east  to  west. 

Insects  and  worms.  A  few  seeds  are  peculiarly  modified 
for  insect  distribution,  as  for  example,  those  of  some  spurges 
and  other  small  plants,  which  have  little  crests  or  grooves  just 
fitted  to  receive  the  jaws  of  ants,  thus  making  them  easily  porta- 
ble by  these  busy  toilers.  Others  are  assisted  in  their  distribu- 
tion by  burrowing  worms,  but  this  always  within  narrow  limits. 

Inanimate  agencies.  Allusion  has  already  been  made  to  the 
inanimate  agencies  which  are  employed  by  plants  as  aids  in 
distribution.  Among  these  are  currents  of  wind,  currents  of 
water  and  in  a  slight  degree  translocations  of  soil.  The  latter, 
best  observed  in  mountainous  regions  where  avalanches  exert 
a  considerable  influence,  is  of  slight  importance  in  Minnesota, 
though  upon  the  hillsides  and  cliffs  along  some  of  the  northern 
lakes,  this  method  of  distribution  exists. 

Wind  currents.  In  plant  distribution  the  most  important 
inanimate  agency  is  doubtless  the  wind.  The  alertness  with 
which  plants  make  use  of  it  in  seed-dissemination  is  well  exem- 
plified by  the  new  population  which  appears  after  a  fire  and 
covers  burnt  places  in  the  forest.  When  the  pines  or  spruces 
are  destroyed  by  fire  it  is  a  fact  of  common  observation  that 
poplars,  maples,  elms,  willow-herbs,  milkweeds  and  other  light- 
seeded  plants  spring  up.  The  well-known  fire-weed  with  its 
purple  panicle  of  flowers  ripens  seeds  that  are  provided  with 
tufts  of  delicate  hairs,  and  when  thrown  out  of  the  pods  in  which 
they  are  produced  the  wind  may  catch  them  and  whirl  them 
away  over  the  tree-tops  for  many  miles.  The  poplars,  too,  and 
cottonwoods  are  famous  for  their  winged  seeds  and  succeed  in 
entering  promptly  a  burnt  tract,  so  that  within  a  year  or  two 
they  have  established  themselves  while  there  are  yet  to  be  found 
probably  none  of  the  heavy-seeded  plants,  like  hickories,  wal- 
nuts and  oaks,  and  but  few  of  the  plants  with  adhesive  seeds 
or  pulp-inclosed  seeds  fitted  for  animal  distribution.  It  is  not 
the  seeds  alone  but  often  the  fruits  of  plants  which  are  trans- 
ported by  the  wind,  as  for  example,  the  maple-fruits,  the  elm- 


Minnesota  Plant  Life.  2  i 

fruits  and  the  fruits  of  a  great  variety  of  dandelion-like  and  sun- 
flower-like plants.  Sometimes  the  whole  plant  is  distributed 
by  the  wind  and  examples  of  this  are  especially  striking  upon 
the  prairie  where  the  wind  has  free  sweep.  Thus,  tumbling 
plants  like  the  Russian  thistle,  the  tumbling  mustard  and  the 
tumbling  grass,  when  their  fruits  are  ripe  separate  all  or  the 
greater  part  of  the  stem  from  its  attachment  and  curve  their 
branches  so  that  the  whole  takes  the  shape  of  a  ball  rolling 
freely  for  miles  over  the  level  prairies  before  the  wind.  Some- 
times the  wind  acts  indirectly  in  the  distribution  of  plants,  as 
for  instance,  when  a  portion  of  the  boggy  shore  of  some  lake 
breaks  loose  and  is  blown  away  to  be  anchored  possibly  under 
new  conditions  across  the  lake. 

Water  currents.  Though  the  agency  of  currents  of  water 
in  transporting  seeds  is  scarcely  so  universally  employed  as  that 
of  the  wind,  it  should  not  be  overlooked.  This  agency  is  par- 
ticularly important  for  heavy-seeded  plants  as  their  seeds  are 
often  borne  along  a  stream  in  its  currents  and  eddies  to  find  a 
lodgment  possibly  miles  below  the  point  where  they  were  intro- 
duced. Other  seeds,  to  facilitate  their  floating,  are  provided 
with  buoyant  apparatus  which  adapts  them  also  for  wind  distri- 
bution. 

Man.  One  very  important  agent  in  plant  distribution  re- 
mains to  be  considered,  namely,  man.  Unlike  the  birds  and 
animals,  man  in  his  migrations  is  not  so  strongly  regulated  by 
the  changing  rhythm  of  the  seasons.  On  the  contrary  the  prin- 
cipal lines  of  migration  of  men  since  the  advent  of  Caucasians 
upon  the  continent  have  been  from  east  to  west,  rather  than 
from  north  to  south.  Roads  and  trails  have  been  beaten  across 
the  plains  and  through  the  forests;  railway  lines  have  been 
built,  binding  distant  portions  of  the  country  together,  and  to 
connect  with  them  steamships  cross  the  seas.  Freights  are  car- 
ried from  one  hemisphere  to  another,  and  along  with  that  for 
which  there  are  invoices  and  bills  of  lading  comes  often  a  con- 
signment of  seeds  of  fruits,  unrecorded  yet  none  the  less  im- 
portant. In  this  manner  some  harmful  weeds  as  well  as  some 
useful  forage-plants  have  reached  the  fields  of  Minnesota.  With 
the  immigration  of  men  and  women  from  Russia  has  come  the 
Russian  thistle ;  from  France  and  England  the  cockles  of  the 


22  Minnesota  Plant  Life. 

wheat;  from  Italy  some  mustards;  indeed,  from  all  the  coun- 
tries of  Europe  plants  have  found  their  way  in  company  with 
man.  Some  of  them  are  later  immigrants  than  others.  Those 
which  crossed  with  the  pilgrim  fathers  are  now  as  much  at  home 
as  those  to  the  manner  born.  Others,  the  advent  of  which 
dates  from  yesterday,  have  not  yet  shown  all  their  capabilities, 
and  doubtless  even  now  the  dangerous  new  weeds  of  the  next 
decade  are  some  of  them  precariously  existing  as  little  colonies 
upon  ballast-heaps  or  along  the  lines  of  eastern  or  western  rail- 
ways. 

Associations  between  migrating  plants.  When  plants  travel 
they  do  not  always  travel  alone,  but  in  company  as  man  does, 
who  when  he  migrates  brings  with  him  his  horses,  oxen,  sheep, 
fowls,  dogs,  and  other  domestic  animals  which  have  become 
attached  to  him.  So  the  plant  when  it  migrates  often  takes 
with  it  other  plants.  Thus  where  the  maples  go,  there  go  also 
those  curious  fungi  that  grow  upon  the  leaves,  looking  like  little 
drops  of  tar.  With  the  willow  as  it  is  uprooted  and  floats  down 
a  stream,  perhaps  finding  a  foothold  for  its  twigs  somewhere 
below,  go  the  lichens  and  mosses  upon  its  bark. 

There  is  something  about  the  proximity  of  certain  kinds  of 
plants  which  is  very  agreeable  to  other  varieties,  so  that  gen- 
erally with  pine  trees  one  finds  wintergreens  associated,  and 
with  peat-mosses,  cranberries.  The  latter  are  not  associations 
like  the  associations  between  the  maple  and  the  fungus  upon  its 
leaves,  but  are  rather  indications  of  kindred  tastes  in  habita- 
tions. The  establishment  of  one  kind  of  plant  over  an  area 
may  be  the  natural  and,  perhaps,  the  necessary  pre-requisite  for 
the  development  of  another  plant  which  has  formed  the  habit 
of  attaching  its  fortunes  to  those  of  the  first  one  in  the  field. 
Plants,  also,  by  their  position  and  attitudes  strongly  influence 
the  distribution  of  other  plants.  If  plants,  which  are  accus- 
tomed to  depend  upon  winged  seeds  for  their  distribution,  find 
themselves  gradually  enclosed  by  the  foliage  of  strong-growing 
neighbors  it  will  be  difficult,  perhaps,  for  them  to  extend  farther 
the  range  of  their  seeds.  Or,  possibly,  the  berries  which  were 
attractive  during  a  season  when  neighboring  plants  were  not  in 
fruit  may  not  be  so  attractive  another  year  when  the  adjacent 
forms  are  ripening  their  own  larger,  more  highly  colored,  more 
highly  scented  or  sweeter  fruit. 


Minnesota  Plant  Life.  23 

Where  the  story  of  plant  migration  is  recorded.  It  is  im- 
possible to  mention  except  in  a  more  extended  account  the 
many  and  various  ways  in  which  plants  influence  the  distribu- 
tion of  each  other  or  receive  influence  from  outside  sources,  but 
enough  has  been  said  to  indicate  the  general  laws  under  which 
the  State  of  Minnesota  has  received  the  plants  which  now 
inhabit  its  territory.  They  have  come  from  all  points  of  the 
compass,  from  all  parts  of  the  world,  bringing  with  them  habits 
acquired  through  countless  generations  of  struggle  and  adapta- 
tion. To  the  enlightened  eye,  the  form  of  a  plant  tells  a  story 
of  its  life  and  of  the  experiences  it  must  have  undergone  to 
develop  one  type  of  structure  rather  than  another.  Just  as  in 
the  formidable  defensive  armor  of  an  extinct  armadillo  may 
be  read  somewhat  of  the  story  of  its  struggle  with  its  enemies, 
so  in  the  three  hundred  feet  of  solid  trunk  and  in  the  massive 
girth  of  a  living  Big-tree  in  the  Sierras  one  may  read  the  story 
of  its  struggle  in  the  ancient  forests  when  its  allies  and  com- 
petitors were  perhaps  more  numerous  and  more  vigorous  in 
their  aspiration  for  light  than  are  the  neighbors  of  to-day. 

In  the  Minnesota  valley,  not  far  from  New  Ulm,  there  are 
found  upon  rocks  exposed  in  the  river-bed  by  the  erosion  of  the 
waters,  some  specimens  of  the  little  prickly-pear  cactus,  a  desert 
plant  which  has  found  its  way  from  the  plains  of  Arizona  and 
New  Mexico.  By  all  its  characters  it  indicates  how  it  must 
have  been  trained  in  a  school  of  life  different  from  that  in  which 
the  plants  around  it  receive  their  education.  Its  solid,  leafless, 
flattened  stem  with  a  resistent  rind  is  fitted  to  withstand  the 
evaporation  of  moisture — a  character  much  needed  in  the  des- 
ert, but  less  necessary  in  the  valley  of  the  Minnesota.  Its 
strong  root  system  extending  out  a  yard  or  more  on  every  side 
was  indispensible  to  collect  what  little  moisture  there  might 
have  been  in  the  arid  soil  of  the  southwestern  desert;  with  a 
smaller  root  system  it  could  do  very  well  in  its  northern  home. 
The  sharp  thorns  and  spines  with  which  it  is  covered  were  a 
necessary  protective  armor  where  vegetation  was  sparse  and 
grazing  animals  hungry ;  without  this  armor  it  could  live  very 
well  on  the  hills  of  New  Ulm,  for  there  dwell  other  plants,  with- 
out armor  nor  do  the  herds  destroy  them.  Such  a  plant,  evi- 
dently a  wanderer  from  another  land,  is  like  a  man  of  mediaeval 


24  Minnesota  Plant  Life. 

times  who  should  be  reincarnated  in  a  modern  society  and 
should  insist  upon  wearing  the  coat  of  mail  and  carrying  the 
rapier  which  were  necessary  in  another  age,  but  would  be  rec- 
ognized as  altogether  out  of  place  in  the  life  of  the  present  day. 

The  pine  trees,  with  their  needle-shaped  leaves  fitted  to  trans- 
pire water  but  slowly  and  with  their  strong  branches  able  to 
carry  the  weight  of  the  snow  which  is  piled  upon  them  in  their 
northern  home,  when  they  find  their  way  down  the  river  to  the 
comparatively  genial  climate  of  Iowa  cannot  at  once  abandon 
the  structures  which  they  developed  under  the  stern  necessity 
imposed  by  the  severer  climate  of  their  native  land.  The  mat- 
plant,  such  as  a  purslane  or  carpet-weed,  adapted  to  life  on  a 
flat  plane  where  it  is  not  shaded  by  surrounding  plants  but 
spreads  out  all  its  prostrate  branches  in  a  discoid  body,  cannot 
erect  itself  into  the  slender  wand  of  the  aster,  taught  to  assume 
this  shape  by  centuries  of  existence  in  the  underbrush  above 
which  it  had  to  lift  its  leaves  that  they  might  catch  the  sun. 
The  aspiring  spruce  telling  in  its  form  a  story  of  other  spruce 
trees  close  beside  it  crowding  each  other  as  they  all  reached 
upward  for  the  light,  if  it  is  planted  in  one's  dooryard  with  noth- 
ing near  to  shade  it  cannot  abandon  the  character  which  it 
developed  of  old.  Plants  when  they  migrate  from  place  to 
place  must  take  with  them  those  structures  and  habits  which 
are  fitted  best  to  the  whole  history  of  their  species.  In  their 
migrations  they  select  places  which  resemble  as  closely  as  pos- 
sible those  to  which  they  are  accustomed.  They  allow  them- 
selves a  certain  freedom  just  as  men  do,  but  even  as  regards  men 
it  is  well-known  that  they  prefer  to  migrate  along  the  same 
parallel  of  latitude,  so  that  the  inhabitants  of  Minnesota  have 
come  rather  from  the  forests  of  New  England  and  New  York, 
from  Canada,  from  Scotland,  and  from  Scandinavia,  than  from 
the  highlands  of  Mexico,  from  Italy,  Africa,  or  Brazil. 

Struggles  of  migrating  plants.  It  must  be  apparent  from 
all  that  has  been  said  that  the  laws  governing  the  migration  of 
plants  are  substantially  the  same  as  those  that  govern  the  migra- 
tion of  other  living  beings.  It  is  an  instinct  with  all  living 
creatures  to  maintain  their  own  existence  as  long  as  they  can 
and  to  do  this  they  wrest  from  others,  weaker  or  less  fortunate, 
the  right  to  food  and  sunshine  which  they  in  their  turn  demand 


Minnesota  Plant  Life.  25 

of  nature.  It  is  even  so  with  men  ;  the  dervishes  of  the  Soudan 
must  give  way  before  civilized  England.  Thus  also  must  the 
feeble  plants  of  a  meadow's  edge  yield  before  the  onslaught  of 
trained  roadside  plants,  brought  in  from  other  parts  of  the 
world  and  fitted  to  cope  with  the  conditions  of  existence  in  a 
stronger  and  better  way.  As  one  looks  at  a  placid  meadow,  its 
grasses  bending  in  the  breeze,  he  should  remember  that  under- 
neath the  calm  serenity  of  the  scene  there  is  a  bitter  struggle, 
a  relentless  internecine  warfare  between  the  plants  that  are 
already  in  the  meadow  and  those  that  are  striving  to  enter 
from  without. 

Comparison  of  plants  with  animals.  Next  to  and  even 
stronger  than  the  instinct  to  exist  is  the  instinct  to  persist,  and 
plants  sacrifice  their  own  lives  for  their  offspring  just  as  readily 
in  their  sphere  of  life  as  will  a  human  mother  give  up  her  life 
for  her  child.  In  dealing  with  plants  the  mind  must  be  rid  of 
the  mistaken  notion  that  they  are  dull,  stupid  things  which  stay 
where  they  are  set  without  ability  to  better  themselves  and 
their  offspring.  On  the  contrary  the  plant  should  be  regarded 
as  a  living  organism  with  definite  necessities  and  definite  in- 
stincts. Plants  are  quite  as  much  alive  as  animals,  and,  indeed, 
they  are  greater  ground-gainers  on  the  surface  of  the  earth 
than  animals  are,  for  if  all  the  plants  of  the  world  should  be 
weighed  in  one  scale  pan  of  a  gigantic  balance  with  all  the  ani- 
mals in  the  other  it  would  be  seen  that  as  organizers  of  dead 
matter  into  living  substance  the  plants  far  outrank  the  animals. 
In  dynamic  force,  in  the  ability  to  apply  energy  in  some  definite 
direction,  the  animal  is  indeed  superior,  but  in  those  purely  con- 
structive vital  powers  no  organisms  are  so  skillfully  adapted  and 
so  perfectly  organized  as  the  plants.  They  are  not  altogether 
of  a  lower  type  of  life  than  animals,  for  they  do  their  work  in 
the  world  after  their  fashion,  and  that  is  all  that  animals  can  do. 
They  are  rather  to  be  viewed  as  other  kinds  of  living  things, 
and  are  to  be  regarded  not  as  merely  subservient  to  the  needs  of 
animals,  not  solely  as  a  food-supply  for  grazing  cattle  or  roving 
birds,  but  of  interest  for  their  own  sake  and  possessing  an  indi- 
viduality to  be  respected. 


Chapter  III. 

Slime-Moulds  and  Blue-green  Algae. 


Number  of  plants  in  the  world.  In  the  whole  world  there 
are  now  living  about  300,000  different  kinds  of  plants,  and  it  is 
possible  that  nearly  as  large  a  number  of  forms  are  extinct. 
The  relics  of  past  plant  life  in  Minnesota  are  not  very  abundant, 
but  in  the  older  rocks  there  are  a  few  fossil  sea-weeds  deposited 
on  the  mud  flats  of  an  ancient  ocean  which  covered  the  region 
now  occupied  by  the  land,  and  in  the  red  sandstone  which  oc- 
curs in  the  Minnesota  valley  in  limited  quantities,  there  have 
been  found  imprints  of  leaves  belonging  to  by-gone  genera. 
For  example,  in  those  days  palm  trees  flourished  in  the  state 
and  have  left  their  replicas  along  with  the  remains  of  red-woods, 
big-trees,  cycads,  magnolias,  tulip-trees  and  other  varieties, 
which  are  not  now  found  within  hundreds  of  miles  of  Minnesota. 
From  old  peat  deposits  and  from  soil  masses  lying  under  the 
glacial  clays,  fragments  of  charred  wood  and  vegetable  debris 
are  sometimes  exhumed.  Such  fossils  often  show  that  the  dis- 
tribution of  plants  before  the  glacial  period  was  quite  different 
from  that  of  to-day. 

Number  and  sorts  of  plants  in  Minnesota.  At  the  present 
time,  of  the  300,000  living  species  of  plants,  about  7,500  are 
probably  to  be  found  growing  without  cultivation  in  Minnesota. 
The  figures  are  in  the  nature  of  an  estimate,  for  by  no  means  so 
considerable  a  number  has  yet  been  discovered.  But  it  must 
be  remembered  that  the  larger  proportion  of  these  plants  are 
not  the  conspicuous  objects  which  are  usually  in  mind  when  the 
word  "plant"  is  used,  but  are  rather  the  insignificant  micro- 
scopic forms,  difficult  to  discover  and  often  of  such  slight  differ- 
ence from  each  other  that  they  would  be  recognized  as  distinct 
varieties  only  by  the  most  trained  observers. 


Minnesota  Plant  Life.  27 

An  estimate  of  the  distribution  of  these  7,500  species  of  Min- 
nesota plants  among  the  different  groups  is  approximately  as 
follows:  slime-moulds  150;  bacteria  and  algae  1,000;  fungi  and 
lichens  3,250;  liverworts  and  mosses  500;  ferns  and  flowering 
plants  2,600.  It  is  evident  then,  that  most  plants  of  the  state 
belong  to  the  lower  orders  of  vegetation. 

There  may  now  be  given  a  general  account  of  the  Minne- 
sota vegetation,  avoiding  the  use  of  technical  terms  and  describ- 
ing where  it  is  possible  certain  common  forms  of  each  group,  so 
that  the  reader  may  have  within  small  compass  a  comprehensive 
view  of  the  classes  just  named,  as  they  are  represented  in  the 
state. 

Slime-moulds.  The  plants  (or  more  probably  animals)  known 
as  slime-moulds  constitute  a  very  peculiar  group  of  organisms. 
It  is  by  no  means  certain  that  they  are  plants  at  all,  although 
they  have  some  vegetable  characters.  In  other  respects 
they  resemble  the  lower  animals,  and  botanists  and  zoolo- 
gists have  often  debated  to  which  of  the  two  great  realms  of  life 
they  really  belong.  One  of  them,  which  is  known  to  occur  in 
Minnesota,  may  possibly  have  come  under  the  observation  of 
some  of  the  readers  of  this  book.  The  roots  of  cabbages  and 
turnips,  when  pulled  from  the  ground,  are  sometimes  found  to 
be  covered  with  a  curious  irregular  growth  of  little  spherical 
tubers,  about  the  size  of  hazel  nuts, — sometimes  larger,  though 
often  very  much  smaller.  The  occasion  of  the  appearance  of 
such  tubers  is  the  development  of  singular  little  slime-moulds 
too  small  to  be  seen  by  the  naked  eye  but  sufficiently  active  to 
cause  gall-like  swellings  in  the  tissues  of  the  root.  Because  of 
the  ruptured  appearance  which  the  root  has  when  affected  by 
these  tiny  organisms,  the  whole  structure,  root  and  slime-mould, 
is  known  as  a  root-hernia  or  as  club-root. 

Most  slime-moulds  do  not,  however,  live  thus  as  parasites  on 
other  plants,  but  are  found  on  decaying  leaves,  rotten  twigs, 
fallen  logs  and  other  debris  of  the  forest-floor  in  shaded  places. 
They  sometimes  grow  up  from  a  mucilaginous  base,  forming 
little  brown,  cylindrical  plumes,  not  more  than  half  an  inch  in 
height  and  clustered  together,  a  score  or  more,  in  a  group.  The 
brown  plumes  are  found  upon  careful  examination  to  be  deli- 
cately woven  masses  of  threads,  between  which  is  a  fine  brown 


28  Minnesota  Plant  Life. 

dust  which  can  be  shaken  out  upon  the  hand  or  upon  a  piece 
of  paper.  This  brown  dust,  under  the  microscope,  is  seen  to 
consist  of  innumerable  tiny  spheres,  the  spores  of  the  plant.  If 
the  spores  be  placed  in  water,  after  a  time  their  shells  break  and 
out  of  each  comes  a  little  mis-shapen  drop  of  jelly-like  substance, 
which  oozes  away  with  a  slow  and  viscid  movement.  If  several 
of  these  tiny  bits  of  jelly  find  themselves  close  together — per- 
haps after  a  rain  upon  the  bark  of  some  rotten  log — they  crawl 
towards  each  other  and  fuse  into  a  common  patch.  The  patch 
then  moves  imperceptibly  over  the  wood,  increasing  in  size  as  it 
extracts  nourishment  from  the  decayed  material.  Sometimes 
the  jelly-masses  grow  to  the  size  of  a  man's  hand.  A  common 
sort  is  found  in  tan  yards  and  often  upon  railway  ties  resembling 
very  much  a  piece  of  ordinary  thin  jelly  and  generally  cov- 
ered with  a  sulphur-colored  powder.  After  the  jelly-mass  has 
increased  in  size  to  a  certain  point  it  breaks  up  into  little  clusters 
which  afterwards  develop  fruit-bodies  more  or  less  like  the 
brown  plumes  spoken  of  above. 

Another  kind  of  slime-mould  crawls  up  the  stems  of  various 
plants  in  meadows  and  deposits  itself  upon  the  leaves  in  little 
foam-patches  looking  very  much  like  drops  of  spittle.  There 
are  some  insects  which  make  similar  spittle-masses  on  leaves  and 
an  expert  investigation  is  necessary  to  determine  whether  such 
objects  are  insect  products  or  the  plant  bodies  of  slime-moulds. 

Some  slime-moulds  have  the  power  of  incrusting  their  tiny 
fruit-bodies  with  lime  which  they  extract  from  their  soil  or  from 
rain-water  that  falls  upon  them.  Such  forms  are  often  observed 
in  Minnesota  upon  dead  wood,  or  fallen  leaves,  generally  in 
moist  shady  places  in  the.  deep  forest.  Sometimes  the  fruit- 
bodies  are  almost  round,  resembling  the  familiar  pills  of  the 
homeopathist.  In  other  species  they  are  worm-like,  coiled  like 
loose  snail-shells,  but  very  much  smaller,  yet  not  so  small  that 
they  cannot  easily  be  discovered  if  searched  for  in  the  places 
that  they  have  chosen.  A  few  slime-moulds  will  be  encountered 
among  mosses,  forming  little  brown  scurfs  upon  the  moss  tuft 
or  displaying  themselves  as  yellowish  patches  around  the  bases 
of  the  leaves.  None  of  these  plants  have  any  economic  import- 
ance. The  most  conspicuous  one  in  Minnesota  occurs  upon 
dead  logs  as  pink,  hemispherical  bodies,  about  the  size  of  the 


nnesota  Plant  Life.  29 


end  of  one's  finger.  Usually  these  fruit-bodies  are  seen  in  clus- 
ters of  a  dozen  or  more.  If  one  of  them  is  cut  into  it  will  be 
discovered  that  the  interior  consists  of  a  brown  moist  powder, 
which  when  dry  blows  away  in  an  impalpable  dust.  In  a  single 
fruit-body  such  as  one  of  these,  millions  of  spores  originate 
which,  washed  away  by  the  rains  or  blown  about  through  the 
atmosphere,  may  fall  upon  suitable  decaying  substances,  open 
and  liberate  each  its  tiny  bit  of  living  jelly  that  by  itself  or  with 
the  assistance  of  others  gradually  builds  up  a  newr  plant-body. 

Algae.  The  plants  known  as  algae  secure  their  best  develop- 
ment in  the  sea,  where  under  the  name  of  sea-weeds  they  are 
universally  known  and  many  of  them  admired  for  their  beauty 
of  color  and  gracefulness  of  form.  Of  the  algae  there  are  five 
principal  groups;  i,  bacteria;  2,  blue-green  algae;  3,  bright- 
green  algae;  4,  brown  algae;  5,  red  algae.  The  red  algae  and 
brown  algae  are  chiefly  marine,  although  a  few  varieties  of  at 
least  the  red  group  are  found  in  the  fresh  wraters  of  Minnesota. 
Most  of  the  algae  in  fresh  waters  belong  to  the  blue-green  or 
bright-green  groups,  while  those  lowly  and  most  extraordinary 
of  plants,  the  bacteria,  are  of  such  various  occurrence  in  soil, 
water,  air,  and  the  bodies  of  other  organisms  that  I  shall  con- 
sider them  in  a  special  chapter. 

Blue-green  algae.  The  plants  of  this  group  may  generally 
be  recognized  by  their  bluish-green  color,  approaching  some- 
times the  hue' of  verdigris  and  never  the  pure  grass-green  which 
distinguishes  the  bright-green  group.  One  of  the  most  com- 
mon of  them  is  the  so-called  "water  flower"  which  in  summer 
develops  in  such  vast  quantities  in  the  lakes  of  Minnesota.  The 
tiny,  bluish,  jelly-ball  of  the  water-flower,  ordinarily  not  larger 
than  a  pin-head,  if  examined  closely  will  be  found  to  have  a  bub- 
ble of  gas  at  the  centre,  by  means  of  which  it  floats.  If  this 
bubble  is  analyzed  by  chemical  methods  it  will  be  ascertained  to 
be  more  highly  oxygenized  than  the  atmosphere.  It  is  pro- 
duced by  the  growth-activities  of  the  plant  and  incidentally 
serves  the  important  purpose  of  keeping  it  near  the  surface  of 
the  water  where  it  may  obtain  the  light.  At  Lake  of  the  Woods 
I  have  seen  these  plants  in  such  enormous  numbers  that  the 
water  looked  more  like  green  paint  than  lake-water  and  at  Lake 
Minnetonka  the  cottagers  often  complain  of  the  abundance  of 


30  Minnesota  Plant  Life. 

the  water-flower  and  inquire  for  methods  of  exterminating  it. 
There  is,  however,  no  practicable  way  of  destroying  it,  for  if  the 
water  should  be  poisoned  enough  to  kill  the  water-flower  other 
living  things,  pond-lilies,  bulrushes  and  bass  would  also  disap- 
pear. 

Structure  of  the  water-flower.  A  microscopic  examination 
of  the  water-flower  will  show  that  each  tiny  jelly-ball  consists 
of  a  number  of  delicate  algal  threads  intertwined  and  imbedded 
in  a  common  mass  of  jelly  which  they  secrete.  When  a  jelly- 
ball  becomes  sufficiently  large  it  commonly  breaks  in  two  and 
the  pieces  continue  growing  as  before.  If  the  jelly  be  dissolved 
hundreds  of  tiny  coiled  threads  escape  from  it  and  multiply, 
developing  hundreds  of  new  jelly-balls.  In  the  autumn  these 
little  creatures  drop  to  the  bottom  of  the  lake,  or  remain  in  a 
dormant  condition  frozen  in  the  ice  until  the  warmth  of  another 
season  stimulates  them  into  renewed  activities. 

Larger  jelly-balls,  in  appearance  very  much  like  green  plums, 
but  with  the  characteristic  bubble  of  gas  at  the  centre  are  often 
found  floating  in  ponds.  These  belong  to  another  species  of 
blue-green  algae  but  they  are  closely  related  to  the  water-flower 
and  their  structure  and  life-habits  are  not  essentially  different. 
Still  another  variety  of  blue-green  algae  is  common  as  little 
hemispherical  lumps  an  eighth  of  an  inch  in  diameter  attached 
upon  the  stems  of  bulrushes,  just  beneath  the  surface  of  the 
water.  Still  other  kinds  form  tufts  and  stringy  masses  several 
inches  in  length  floating  near  the  surface  of  stagnant  pools.  A 
curious  form  which  has  lost  the  blue-green  color,  and  may  be 
classed  also  as  a  bacterium,  is  sometimes  found  growing  in  the 
outlets  of  springs,  where  it  resembles  a  mass  of  iron  rust  dis- 
solved in  water.  The  red  color  is  not  a  deception  for  it  is  ac- 
tually due  to  iron  oxide  extracted  from  the  water  by  the  micro- 
scopic filaments  of  the  plant. 

Rock-forming  algae.  Some  of  the  blue-green  algae  have 
the  power  of  encrusting  themselves  with  lime,  and  in  watering- 
troughs  and  tanks  there  sometimes  occurs  a  calcareous  forma- 
tion reminding  one  of  the  deposit  in  old  tea-kettles.  Such  a 
crust  is  true  limestone  extracted  from  the  water  by  the  chemical 
activities  of  the  algae.  Upon  a  large  scale  the  blue-green  algae 
play  their  part  in  the  formation  of  rock.  The  best  place  in 


Minnesota  Plant  Life. 


America  and,  indeed,  in  the  world,  to  observe  their  action  is  at 
the  Yellowstone  National  Park,  where  great  masses  of  traver- 


FIG.  8.— Portion  of  a  board  which  had  been  standing  in  the  tank  shown  in  fig.  10.  It  is  en- 
crusted with  lime  stone  deposited  by  a  colony  of  blue-green  algae.  After  photograph  by 
Miss  Josephine  E.  Tilden.  From  the  Botanical  Gazette. 

tine  and  sinter  are  formed,  covering  acres  around  the  hot  springs 
in  which  the  blue-green  rock-forming  algae  find  a  congenial 
home.  Travertine  is  a  kind  of  limestone;  sinter  is  a  kind  of 


32  Minnesota  Plant  Life. 

silica  or  sand  rock  and  it  therefore  appears  that  not  only  can 
some  blue-green  algae  extract  lime  salts  from  the  water,  but 
other  varieties  can  form  quartz  as  well.  No  doubt  very  much 
of  the  limestone  and  even  of  the  granite  that  occurs  in  ledges 
over  the  continent  was  begun  in  ancient  warm  seas  by  the  action 
of  organisms  similar  to  the  blue-green  algae,  while  at  the  Yel- 
lowstone Park,  or  upon  a  smaller  scale  in  one's  watering  trough, 
the  same  rock-forming  processes  are  still  going  on. 

Skin-algae.  Still  another  variety  of  blue-green  alga  produces 
broadly  expanded  membranes,  or  skins,  along  the  bottom  of 
springs,  and  on  pebbles  in  streams  or  lakes.  In  general  the 
plants  of  this  group  may  be  recognized  by  their  color  and  they 
are  among  the  lowest  of  the  algae. 


Chapter  IV. 

Bright-green  Algae* 


By  far  the  greater  number  of  Minnesota  algae  belong  to  this 
group. 

Pond-scums.  Probably  the  most  easily  recognized  is  the 
familiar  pond-scum,  which  is  by  many  people  regarded  with 
aversion  and  is  supposed  to  be  in  some  mysterious  way  con- 
nected with  the  presence  of  frogs.  If  the  slimy  bright-green 
scum.be  lifted  from  the  pool,  taken  upon  the  fingers  and  closely 
examined,  it  will  be  seen  to  consist  of  long  delicate  unbranched 
hairs.,  .not  much  thicker  than  a  spider's  web.  As  it  dries  in  the 
hand  it  curls  and  sh-rivels,  but  under  the  microscope  the  hairs  are 
beautiful  objects.  They  are  jointed  and  in  each  joint  lie  coiled 
one  or  more  green  bands,  like  ribbons  in  a  glass  jar.  By  means 
of  the  green  bands  the  plant  can  construct  starch  out  of  the 
carbonic-acid  gas  in  the  bubbles  of  air  scattered  near  it  through 
the  water,  using  also  the  water  itself  in  the  process.  By  the 
breaking  of  the  threads  between  their  joints  the  plant  abund- 
antly propagates  itself  throughout  the  summer. 

When  autumn  arrives  a  very  remarkable  breeding-habit 
comes  into  play.  Two  of  the  pond-scum  threads  extend  them- 
selves close  together  in  the  patch  and  from  the  joints  of  each, 
little  protuberances  arise  which  become  blended  into  tunnels, 
uniting  ordinarily  the  joints  of  one  filament  to  the  neighboring 
joints  of  an  adjacent  filament.  Through  such  tunnels  the  entire 
living  contents  of  one  joint  creep  over  and  combine  with  the 
living  contents  of  a  neighboring  joint.  The  fused-body  then 
contracts  like  a  sponge,  expressing  much  of  its  sap  and  secreting 
about  itself  a  firm  clear  membrane.  After  such  a  process, 
repeated  throughout  the  patch  of  algae,  the  walls  of  the  old 
joints  may  slowly  break  or  dissolve,  and  the  hundreds  or  thou- 
sands of  oval  fused-bodies,  inclosed  in  their  special  membranes 
drop  to  the  bottom  of  the  pool,  where  they  lie  dormant  until  the 


34 


Minnesota  Plant  Life. 


following  spring.  Then  each  membrane  dissolves  or  breaks  and 
the  fused-body  extends  itself  into  a  new  pond-scum  thread, 
becoming  jointed  as  it  grows  and  elaborating  in  each  of  the 
joints  the  green  ribbons  by  means  of  which  it  pro- 
duces its  food  from  water  and  carbonic-acid  gas  just 
as  did  its  parents  the  preceding  season.  By  the 
breaking  in  pieces  of  this  filament  in  the  way  that 
has  been  described  and  by  the  subsequent  growth 
of  the  pieces  a  large  patch  of  scum,  enough  to 
cover  the  surface  of  a  small  pool,  will  be  produced 
before  the  summer  is  at  an  end. 

Desmids.  Related  to  the  pond-scum  are  a  large 
number  of  tiny  crescent-shaped  and  star-shaped 
plants  called  desmids.  These  are  often  particularly 
well-developed  in  the  water  of  peat-bogs,  so  that  if 
one  goes  to  the  nearest  tamarack  swamp  and 
brings  away  a  tumbler  full  of  water  which  he  has 
squeezed  out  from  among  the  peat-mosses,  and  sets 
the  tumbler  in  the  window,  within  a  few  hours  a 
green  film  of  desmids  will  be  likely  to  form  upon 
the  side  of  the  glass  turned  toward  the  light.  Like 
the  pond-scums  these  little  plants  have  their  breed- 
ing habits  and  like  them  they  are  able  to  maintain 
and  distribute  themselves  throughout  the  water  of 
their  pool.  If  in  the  autumn,  the  pool  becomes 
dry,  the  little  eggs  of  the  desmids  lying  among  the 
particles  of  soil  may  be  caught  up  by  the  wind 
and  carried  to  distant  pools  where  they  continue 
developing  as  before. 

Rolling  algae.  Not  uncommon  in  Minnesota 
is  another  bright-green  alga  which  appears  in  quan- 
tity in  pools  as  green  globules  somewhat  smaller 
than  pinheads.  If  placed  in  a  saucer  of  water  and 
observed  closely  one  of  these  green  globules  will 
be  seen  to  roll  over  and  over  in  the  water  and  make 
its  way  from  one  side  of  the  saucer  to  the  other. 
It  does  this  because  its  surface  is  covered  with  tiny  contractile 
threads,  which  lash  about  in  the  liquid  like  so  many  little  whip- 
cords and  roll  the  whole  ball  from  one  point  to  another  as  the 


FIG.  9. —  Portion 
of  a  pond-scum 
thread,  show- 
ing how  it  is 
made  up  of 
transparent- 
walled  cells 
with  a  coiled 
green  ribbon 
in  each,  much 
magnified. 
After  Atkin- 
son. 


Minnesota  Plant  Life. 


35 


needs  of  the  plant  may  determine.     Because  of  its  rolling  habit 
this  little  plant  is  called  Volvox,  or  the  rolling  alga. 

Flower-pot  algae.  Somewhat  related  to  the  Volvox,  but  by 
no  means  so  interesting  an  object,  is  the  bright-green  alga  which 
forms  a  scurf  on  flower-pots  in  green-houses,  upon  curbstones 
near  hydrants,  upon  the  foundation  stones  of  houses  standing 
upon  damp  places,  upon  damp  soil,  and  often  upon  fallen  trees 
in  the  deep  forest.  A  microscopic  examination  of  the  green 


FIG.  10.  Patches  of  pond-scum  floating  in  a  tank.  A  lime-encrusting  alga  grows  on  the 
boards  up  to  high-water  mark.  Near  Minneapolis.  After  photograph  by  Mr.  R.  W. 
Squires. 

scurf  on  a  flower-pot  would  show  that  it  is  made  up  of  countless 
very  tiny  green  spheres,  fifty  of  which  could  be  laid  side  by 
side  across  the  dot  over  a  lower  case  "i"  on  this  page.  The  way 
in  which  these  little  plants  multiply  is  as  follows :  While  they 
are  finding  food  in  plenty  in  the  moisture  about  them,  the  con- 
tents of  each  of  the  spheres  will  be  seen  to  divide  into  two,  four 
or  eight  smaller  balls.  The  membrane  of  the  old  sphere  then 
dissolves  and  the  little  balls  tumble  out  and  grow  to  the  size  of 


36  Minnesota  Plant  Life. 

the  one  which  produced  them.  This  process  .is  rapidly  repeated 
and  in  a  few  days  such  a  geometric  progression  will  bring  into 
existence  an  enormous  number.  A  variation  of  the  process 
sometimes  occurs  when  there  is  an  unusual  abundance  of  mois- 
ture, as  after  a  heavy  rain.  Each  of  the  little  balls  formed  under 
these  circumstances  is  provided  with  a  pair  of  extremely  delicate 
lashes  by  means  of  which  it  propels  itself  through  the  water 
with  a  curious  rotating  and  wabbling  movement,  something  like 
that  of  a  rifle-ball,  only,  of  course,  very  much  slower.  It  takes 
some  moments  to  travel  an  inch,  yet,  on  account  of  the  very 
small  size  of  the  plant,  its  movements  viewed  under  a  microscope 
seem  fairly  agile. 

Red  snow.  The  famous  red-snow  plant,  which  is  found  upon 
mountain  heights  in  the  Alps,  in  Bolivia^  or  in  the  Selkirks,  is  a 
relative  of  the  green-slime  so  common  upon  flower-pots  in  the 
Minnesota  conservatories.  The  color  of  the  red-snow  plant  is 
adapted,  no  doubt,  to  the  cold  region  which  it  has  chosen  for 
growth,  and,  in  general,  red  coloring  substances  in  plants  have 
been  described  as  warining-up  colors — thus  the  autumn  leaves 
turn  red  not  because  they  are  dying  but  for  very  much  the  same 
reason  that  men  wear  overcoats  and  woolens.  Redness  may 
be  regarded  as  one  of  the  plant's  ways  of  protecting  itself  against 
a  low  or  falling  temperature. 

Water-nets.  Among  the  bright-green  algae  a  conspicuous 
but  not  extremely  common  form  in  Minnesota  is  the  water-net. 
This  plant  grows  in  quiet  pools  and  resembles  very  much  a  piece 
of  green  mosquito-bar  rolled  up  in  an  irregular  cylinder,  three 
or  four  inches  long,  and  an  inch  or  more  in  diameter.  Each 
side  of  a  mesh  in  the  net  is  a  joint  or  cell  of  the  plant,  and  in 
each  cell  the  living  contents  have  the  power  of  arranging  them- 
selves into  a  tiny  net.  When  the  wall  of  an  old  cell  dissolves 
the  tiny  net  begins  to  grow,  enlarging  all  of  its  mesh-sides 
equally,  until  it  has  become  as  large  as  its  parent.  Besides  this 
propagative  process  the  water-net  has  the  power  of  breeding 
somewhat  as  does  the  pond-scum,  and  produces  curious  little 
microscopic  jackstone-shaped  fused-bodies  which  remain  dor- 
mant at  the  bottom  of  pools  during  the  winter  months.  A 
great  variety  of  bright-green  algae  are  found  growing  upon  peb- 
bles, upon  the  stems  of  submerged  vegetation  and  upon  twigs  or 


Minnesota  Plant  Life. 


37 


branches  which  have  fallen  into  the  water.  Their  characters 
are  all  more  or  less  similar  to  those  which  have  been  already  de- 
scribed. 

Leaf-dwelling  algae.  One  remarkable  alga,  very  rare  in  Min- 
nesota, is  found  in  a  peculiar  habitat.  On  the  leaves  of  the 
jack-in-the-pulpit  there  may  occasionally  be  noticed  watery  blis- 
ters, in  which,  under  the  epidermis  of  the  leaf,  slender  green 
threads  branch  and  grow,  giving  a  pale  green  tint  to  the  central 
portion  of  the  blister.  Here  is  an  example  of  a  parasitic  alga, 
forms  similar  to  which  are  more  frequent  upon  leaves  in  tropical 
forests  than  in  temperate  regions. 

Sphere-algae.  Another  bright  green  alga  which  appears  to 
be  uncommon  in  Minnesota,  but  sometimes  forms  floating  tufts 
of  slender  green  threads  in  the  waters  of  overflowed  meadows, 
is  remarkable  for  its  production  of  true  eggs  and  spermatozoids. 
As  in  the  pond-scum,  each  thread  of  the  body  is  an  unbranched 
row  of  joints  or  cells  all  of  which  are  shaped  like  long  glass 
cylinders  closed  at  each  end.  In  some  of  these  cells  the  living 
contents  break  up  into  a  dozen  or  more  spherical  green  eggs, 
which  lie  close  against  the  wall  of  the  mother-cell  and,  by  fer- 
ments which  they  secrete,  make  little  punctures.  Other  cells 
of  the  filament  convert  their  contents  into  thousands  of  motile 
spermatozoids  which  dart  about  in  the  cell-cavity  in  a  compli- 
cated dance  which  finally  results  in  some  of  them  perforating 
the  wall,  and  through  the  apertures  all  escape  into  the  water. 
After  swimming  about  for  a  time  many  of  them  find  their  way 
through  the  pin-holes  which  the  eggs  had  made  in  the  walls  of 
their  mother-cells.  They  enter  the  egg-mother-cells  and  one  of 
them  buries  itself  in  the  substance  of  each  egg.  When  the  eggs 
in  a  tube  have  been  thus  fecundated  each  encloses  itself  in  a 
spiny  membrane,  assumes  an  orange  color,  and  after  the  wall 
of  the  mother  cell  has  broken  or  dissolved  each  fused-body 
escapes  into  the  water  and  divides  internally  into  a  little  group 
of  spores.  The  spores  in  turn  escape  and  develop  new  filaments 
of  the  alga.  This  alga  is  called  the  sphere-alga  on  account  of 
the  tubes  full  of  spherical  eggs  which  characterize  it. 

Green  felts.  Among  the  other  algae  of  this  group  should 
be  mentioned  the  green-felts  which  form  plush-like  masses  in 
springs  and  ditches.  They  are  remarkable  for  the  unjointed 


38  Minnesota  Plant  Life. 

character  of  their  filaments  and  their  breeding  habits  remind 
one  in  some  respects  of  the  sphere-alga,  for  they  form  true  eggs 
and  spermatozoids. 

Bass-weeds.  Of  all  the  algae  of  Minnesota,  the  largest  and 
most  conspicuous  are  the  bass-weeds.  These  plants  are  familiar 
to  fishermen  because  tufts  of  them  are  commonly  entangled  by 
trolling-hooks  which  have  been  dragging  along  the  bottom  out- 
side the  bulrushes.  The  bass-weeds  have  stems  the  thickness 
of  a  knitting  needle,  with  distinct  nodes  and  internodes.  Upon 
the  nodes  whorls  of  branches  are  produced  and  upon  the 
branches  subsidiary  leaflets.  The  whole  plant,  in  the  more 
common  form,  is  encrusted  with  a  limestone  deposit,  which 
gives  it  a  brittle  and  stony  feeling  to  the  touch.  Hence  these 
plants  are  also  called  stone-worts.  Many  of  them  have  the  habit 
of  forming  diminutive  bulbs  which  separate  and  serve  to  propa- 
gate the  plant,  and  they  also  produce  near  the  bases  of  their 
leaflets  very  definite  oval,  brown  eggs,  not  much  larger  than  a 
pin-point  and  inclosed  in  a  little  spirally  twisted  jacket  of  cells 
leaving  an  opening  at  the  top  through  which  the  spermatozoids 
can  enter.  The  spermatozoids  are  derived  from  curious  little 
spherical  organs  of  a  reddish  color,  and  each  spermary,  not 
larger  than  a  small  pin-head,  forms  as  many  as  30,000  actively 
moving  spermatozoids,  thousands  of  which  are  destined  to  be 
lost  in  the  water,  but  enough  are  produced  so  that  the  eggs  are 
reasonably  certain  of  fecundation  and  may  then,  after  a  dormant 
period  which  extends  over  the  winter  months,  develop  into  new 
bass-weed  plants.  During  the  cold  weather  the  eggs  and  many 
of  the  propagative  bulbils  lie  safely  at  the  bottom  of  the  lake  too 
deep  to  be  injured  by  the  frosts. 

Some  varieties  of  bass-weeds,  slenderer  than  the  others,  are 
not  provided  with  the  limestone  sheath  which  characterizes  the 
more  common  form,  but  may  be  recognized  by  their  general 
similarity  of  structure.  When  taken  out  of  the  water  they  are 
limp,  though  not  slimy  like  the  pond-scums.  Bass-weeds  form 
an  extremely  abundant  vegetation,  generally  distributing  them- 
selves in  the  deeper  waters  of  a  lake,  outside  the  zone  of  pond- 
weeds,  or  of  bulrushes.  Sometimes  they  are  very  common  in 
shallow  waters,  and  I  have  seen  them  in  Glenwood  lake,  and  in 
some  of  the  northern  lakes  of  Minnesota,  growing  vigorously 
in  water  only  a  few  inches  deep. 


Chapter  V. 
Brown  Algae  and  Red  Algae* 


Brown  algae.  Almost  all  of  the  true  brown  algae  are  marine 
and  they  are  remarkable  as  comprising  the  longest  plants  in  the 
world.  It  is  a  popular  impression  that  the  big-trees  of  Cali- 
fornia, the  Eucalypti  of  Australia  and  the  Rotang  palms  of  Java 
and  the  Orient  are  the  longest-stemmed  plants  in  existence. 
This,  however,  is  a  mistake  for  some  of  the  gigantic  seaweeds 
of  the  Antartic  ocean  extend  their  stems  for  over  a  thousand 
feet,  making  them  nearly  three  times  as  long  as  the  trunk  of  the 
tallest  big-tree  in  Calaveras  county,  California.  Such  huge  brown 
algae  are  not  unknown  along  the  sea-coast  of  the  United  States, 
and  the  giant  kelp  of  Puget  sound  sometimes  reaches  a  length 
of  more  than  three  hundred  feet.  By  means  of  its  long  cable- 
like  axis,  it  attaches  itself  to  the  rocks  and  floats  its  immense 
leaves  many  fathoms  out  upon  the  surface  of  the  sea.  Other 
brown  sea-weeds  develop  enormous  strap-shaped  leaves  in  tufts, 
attached  by  hold-fasts  to  the  rocks.  Some  of  them  have  their 
leaves  perforated  with  numerous  holes,  an  adaptation  to  prevent 
them  from  being  torn  by  the  waves.  In  the  fresh  waters  of  Min- 
nesota no  such  forms  as  these  are  to  be  found  and  the  most 
abundant  ones  are  doubtfully  to  be  classed  as  brown  algae  at  all, 
but  from  their  brownish  or  olive-green  color  they  may  here  be 
considered  as  if  certainly  members  of  the  group. 

Diatoms.  In  the  early  spring,  in  rivers,  one  often  finds  olive- 
green  membranous  masses  as  large  as  one's  closed  fist  floating 
idly  at  the  water's  edge.  An  examination  of  them  would  show 
that  they  consist  of  great  numbers  of  microscopic  boat-shaped 
bodies,  with  clear  glassy  walls  and  olive-green  or  brown  con- 
tents. Such  algae  are  known  as  diatoms.  They  sometimes 
occur  in  great  fossil  deposits,  and  in  this  condition  are  much 
prized  for  polishing  powder.  The  walls  of  the  diatom  cells 


4O  Minnesota  Plant  Life. 

have  the  power  of  depositing  in  their  interstices,  silica,  and  it  is 
this  which  gives  the  polishing  quality  to  the  fossil  powder. 

Some  diatoms  are  provided  with  slender  gelatinous  stalks,  by 
means  of  which  they  attach  themselves  to  objects  under  the  sur- 
face of  the  water,  but  many  of  them  are  free-swimming  organ- 
isms. The  exact  mechanism  by  which  they  swim  has  long  been 
a  puzzle  to  students  of  the  group,  for  they  are  not,  like  the  switn- 
ming  cells  of  the  green-slime  which  grows  on  flower-pots,  pro- 
vided with  conspicuous  lashes  by  means  of  which  they  roll  them- 
selves through  the  water.  Most  of  them  seem  to  have,  how- 
ever, extremely  small  apertures  in  their  walls  through  which 
the  living  substance  probably  protrudes  itself  and  sets  up  an 
agitation  in  the  water,  so  that  the  tiny  boat  moves  mysteriously 
across  the  field  of  view  of  the  microscope  like  some  infinitesimal 
electric  launch. 

Red  algae..  This  group  like  the  brown  algae  is  essentially 
marine  and  but  few  forms  are  found  in  the  fresh  waters  of  Min- 
nesota. In  rapidly  flowing  streams  or  under  cataracts  certain 
kinds  display  their  red  bodies,  appearing  as  delicate  plumes  a 
few  inches  in  length  or  as  little  pink  or  purple  plates  an  eighth 
of  an  inch  or  less  in  diameter.  Their  structure  is  more  compli- 
cated than  that  of  any  of  the  algae  which  have  been  considered. 
They  are  supplied  with  egg-cells  from  which  long  cylindrical 
protuberances  are  developed.  The  spermatozoids,  unlike  those 
of  the  sphere  algae,  have  no  swimming  lashes  and  are,  therefore, 
carried  to  the  protuberances  of  the  eggs  by  currents  of  water, 
or  by  the  ministration  of  aquatic  insects,  recalling  in  this  latter 
adaptation  the  extraordinary  relation  which  exists  between 
insects  and  flowers.  When,  however,  a  little  spherical  spermato- 
zoid  comes  in  contact  with  the  slender  cylinder  developed  on 
the  egg-cell,  it  adheres  and  fuses  and,  as  a  result  of  its  stimula- 
tion, from  the  egg  are  thrust  out  branches  which  finally  develop 
spores,  and  thus  the  plant  persists  from  one  generation  to 
another. 

Some  kinds  of  red  algae  are  so  faintly  red  that  they  would  be 
mistaken  for  brown  algae,  if  color  alone  determined  the  classi- 
fication. Such  are  certain  rather  stiff,  wire-like  plants,  spar- 
ingly branched  and  preferring  for  the  most  part  the  same  rapid 
foaming  water  which  the  easily  recognizable  varieties  select  as 


Minnesota  Plant  Life.  ^r 

an  habitation.  Yet  on  account  of  their  various  structural  pecu- 
liarities botanists  assign  them  to  the  group  of  red  algae. 

General  remarks  about  algae.  The  account  that  has  been 
given  is  very  elementary  and  the  reader  must  remember  that  it 
covers  perhaps  as  many  as  a  thousand  varieties,  most  of  which, 
are  species  of  bright-green  algae  and  diatoms.  None  of  the 
fresh-water  algae  has  any  great  economic  importance.  Some 
sea-weeds  are  employed  in  the  manufacture  of  iodine,  others, 
especially  the  kelps,  as  fertilizing  material  for  farms  near  the 
sea-shore.  The  "Irish  moss,"  as  it  is  called,  is  a  red  alga  and 
is  used  for  food ;  when  cooked  it  is  a  kind  of  blanc-mange.  In 
China  several  other  kinds  of  sea-weed  are  regarded  as  edible. 
The  Indian  fishermen  in  Alaska  use  the  stem  of  the  giant  kelp 
as  siphons  and  for  fishing  lines.  In  Minnesota  the  algae  are 
sometimes  rather  noxious  than  useful.  Blue-green  algae  in 
decaying  masses  are  known  to  give  to  the  water  a  characteristic 
pig-pen  odor  which  is  very  offensive.  It  is  at  times  a  difficult 
problem  to  prevent  them  from  vitiating  aqueducts  and  reser- 
voirs, and  cattle  are  reported  to  have  been  poisoned  by  drinking 
water  which  contained  their  rotting  remains.  It  is,  therefore, 
not  the  water  which  contains  the  bright  grass-green  pond-scums 
that  is  so  objectionable,  though  on  account  of  the  slimy  charac- 
ter of  these  plants  they  are  more  repugnant  to  most  people  than 
the  verdigris-colored  water-flower.  Cattle  should  not  be  allowed 
to  drink  from  pools  in  which  the  algal  vegetation  is  of  a  blue- 
green  shade,  but  no  injury  is  likely  to  result  if  the  scums  are 
bright-green. 

In  past  time  it  should  be  remembered  that  certain  lime- 
secreting-algae  and  silica-secreting  algae  have  no  doubt  done 
their  part  in  creating  the  building-stones  of  the  state.  Even  the 
quartzites  and  the  granites  may  be  the  modified  sinter  deposits 
from  some  hot-water  algal  vegetation  of  former  ages.  In  the 
sea,  to-day,  countless  millions  of  algae  are  busy  building  coral- 
reefs  similar  to  those  produced  by  the  coral  polyp,  while  nearer 
home,  in  Lake  Michigan,  limestone  pebbles  have  been  found  to 
be  produced  by  the  concretionary  growth  of  lime-secreting 
algae.  I  have  not  yet  found  any  of  these  algal  pebbles  in  the 
lakes  of  Minnesota,  but  it  is  probable  that  they  occur.  If  any 
one  should  chance  to  find  calcareous  pebbles  the  size  of  an  egg, 


42  Minnesota  Plant  Life, 

which  upon  being  broken  have  a  moist  bluish-green  interior  or 
are  hollow,  he  will  doubtless  have  discovered  a  growth  of  rock- 
forming  algae. 

Algae  the  oldest  kinds  of  plants.  The  great  group  of 
algae  is  of  peculiar  interest  to  students  of  nature  because  it 
includes  the  oldest  types  of  plants  living  upon  the  earth.  There 
is  reason  to  suppose  that  life  originated  in  the  sea,  and  that  all 
the  terrestrial  forms  are  descendants  of  those  which  in  distant 
epochs  learned  to  leave  the  ocean  and  establish  themselves  upon 
the  land.  One  reason  for  supposing  this  is  that  in  distant  peri- 
ods of  the  earth's  history  there  was  very  little  land  in  existence, 
and  almost  the  whole  surface  of  the  globe  was  covered  by  the 
waters  of  the  ocean.  No  doubt,  at  first,  before  the  ocean  had 
cooled,  when  the  world  was  still  young,  warm-water  algae, 
among  which  the  rock  builders  are  so  prominent,  came  into 
being  and  began  their  work  perhaps  among  the  very  first  living 
creatures  of  all  the  hosts  that  now  exist.  Some  varieties  of  land- 
plants  at  present,  as  for  example  the  mosses  and  liverworts,  show 
clearly  in  their  structure  their  relationship  to  the  algae,  and 
serve  as  connecting  links  between  the  great  primal  flora  of  the 
ocean  and  the  modern  flora  of  the  land.  The  algae,  then,  are 
the  forms  from  which  all  other  plants  are  supposed  to  have  orig- 
inated. The  history  of  life  upon  the  earth  is  one  of  constant 
improvement,  and  as  land  appeared  improved  forms  of  algae 
tenanted  it,  and  may  have  given  rise  to  all  the  myriad  higher 
species  of  forest  and  prairie  as  they  are  now  exhibited  over  the 
continents  of  the  world.  And  finally  there  are  very  many  excel- 
lent reasons  for  regarding  the  continents  themselves  to  have 
arisen  largely  through  the  activities  of  living  organisms — a  proc- 
ess that  may  be  observed  continuing  even  in  these  days  if  one 
should  visit  the  coral-islands  of  the  south  seas,  those  enchanted 
atolls  of  the  Pacific. 


Chapter  VI. 

The  Lower  Sorts  of  Fungi. 


Number  of  fungi  in  Minnesota.  While  there  are  nearly  200,- 
ooo  known  species  of  flowering  plants  in  existence,  there  have 
been  described  only  about  50,000  species  of  fungi.  Yet  in  Min- 
nesota, while  there  are  but  2,500  or  2,600  flowering-plants  grow- 
ing without  cultivation  there  are  probably  not  less  than  3,000 
fungi,  so  that  the  state  furnishes  a  field  for  the  development  of  a 
greater  comparative  proportion  of  fungi  than  of  flowering 
plants.  Like  the  mosses  and  liverworts,  the  fungi  are  believed 
to  have  arisen  from  primitive  algal  types  and  students  recognize 
two  principal  series.  The  lower  series  known  as  the  algal  fungi, 
the  structure  of  which  is  more  directly  suggestive  of  algae,  is 
much  poorer  in  forms  than  the  higher  series  of  true  fungi  in 
which  all  the  peculiar  fungal  structures  and  characters  have  had 
an  opportunity  to  be  unfolded. 

Black  moulds.  Of  the  algal  fungi  a  very  widely  distributed 
group  is  that  of  the  moulds.  Among  these  the  black  mould  is 
omnipresent,  and  easily  cultivated.  If  a  slice  of  bread  be  dipped 
in  water,  placed  in  a  saucer,  a  tumbler  inverted  over  it  and  then 
set  in  a  warm  place,  perhaps  behind  the  kitchen  stove,  in  a  few 
days  the  tumbler  will  be  filled  with  a  white  cloud  of  fungus 
threads  and  presently  little  black,  spherical  spore-cases  will  arise 
at  various  points  on  the  fungus  network.  The  white  threads 
are  the  vegetative  plant-body  of  the  mould;  the  black  knobs 
(white  when  young),  smaller  than  a  pin-head,  are  the  fruit-bod- 
ies. The  black  color  of  each  fruit-body  is  occasioned  by  the 
presence,  in  a  swollen  cell,  of  some  hundreds  of  little  black 
spores,  which  have  developed  by  the  division  of  the  living  con- 
tents of  their  mother-cell  or  spore-case.  When  the  spore-cases 
are  broken  and  the  living  powder  is  disseminated,  it  is  caught 
in  air  currents  and  is  held  suspended  in  the  atmosphere  to  such 


44  Minnesota  Plant  Life, 

an  extent  that  in  the  dust  of  the  air  in  every  living'  room  in  Min- 
nesota, hundreds  of  such  spores  are  already  floating.  It  is  nec- 
essary, therefore,  only  to  dip  the  slice  of  bread  in  water  and  set 
it  aside,  for  the  spores  which  have  fallen  upon  it  in  the  process 
to  begin  their  development.  It  would  be  a  mistake  to  suppose 
that  moulds  originate  spontaneously.  A  mould  plant  can  no 
more  come  into  existence  without  the  cooperation  of  some 
mould-spore  than  could  an  oak-tree  without  the  assistance  of  an 
acorn.  It  is  because  of  the  presence  almost  everywhere  of  incal- 
culable numbers  of  mould  spores  floating  invisibly  in  the  atmos- 
phere that  this  seeming  spontaneity  of  development  impresses 
one.  There  are,  however,  many  places  where  bread  will  not 
quickly  mould  if  set  out  in  a  saucer,  for  example,  if  carried  to 
some  high  mountain  top  where  the  air  is  pure  and  free  from 
spores,  or  if  exposed  in  a  chamber  which  has  been  purified  and 
sterilized  by  a  spray  of  carbolic  acid. 

The  black  moulds  have  a  breeding  habit  reminding  one  of  the 
pond-scums.  Two  of  the  white  threads  close  together  or  touch- 
ing each  other,  may  develop  little  side  branches  the  ends  of 
which  blend  and  gradually  convert  themselves  into  a  black 
fused-body  with  very  much  the  character  of  a  fecundated  egg 
and  capable  of  growing  into  a  new  mould  thread. 

Other  kinds  of  moulds.  There  are  several  other  varieties  of 
moulds  belonging  to  this  group  of  algal-fungi,  but  the  well- 
known  blue-moulds,  or  green-moulds,  with  their  verdigris  col- 
ored fruit-bodies  are  classified  in  a  higher  group.  Some  of  the 
moulds  have  curious  habits.  One,  called  the  pill-throwing 
mould,  produces  a  mass  of  spores  upon  the  end  of  a  filament, 
then  underneath  this  mass  there  develops  a  swollen  cell  in  which 
pressure  is  exerted,  so  that  after  a  time  the  mass  of  spores  is 
shot  off  into  the  air  by  the  explosive  mechanism  of  the  stalk-cell. 

Moulds  on  moulds.  Still  another  mould  has  the  peculiarity 
of  attaching  itself  to  the  vegetative  body  of  .the  black  mould.  It 
lives  as  a  kind  of  mould-louse,  extracting  its  nutriment  from  the 
body  of  the  larger  and  more  vigorous  black  mould.  A  plant 
which  thus  fastens  itself  upon  another  living  creature  and 
absorbs  nutriment  from  it  to  the  injury  of  the  host  is  called  a 
parasite. 


Minnesota  Plant  Life0  45 

Fly-cholera  fungi.  Related  to  the  moulds  are  the  singular 
fly-cholera  fungi.  Many  persons  will  have  noticed  sticking  to 
the  window-panes  in  autumn  the  dead  bodies  of  flies  surrounded 
for  some  distance  by  a  faint  yellowish  film  upon  the  glass.  This 
film  consists  of  spores  of  the  fly-cholera  fungus  which  have  been 
shot  into  the  air  by  a  mechanism  similar  to  that  described  for  the 
pill-throwing  mould.  The  vegetative  body  of  the  fly-fungus 
lives  within  the  body  of  the  fly  where,  growing  luxuriantly,  it 
interferes  with  the  life-processes  of  the  insect,  kills  it,  and  con- 
verts a  large  portion  of  its  body  into  food  for  its  own  use.  Other 
flies  approaching  the  infected  individual  are  peppered  with  the 
tiny  spores  of  the  fungus,  or  they  receive  the  contagion  while 
walking  upon  an  infected  window  pane  or  in  a  spore-strewn  cor- 
ner. In  this  way  every  autumn  unnumbered  millions  of  flies 
are  killed.  A  closely  related  cholera-fungus  Attacks  the  Rocky 
mountain  locust  and  is  of  great  economic  importance  because  it 
keeps  this  dangerous  insect  in  check.  Still  other  varieties 
attack  other  insects,  but  these  two  will  serve  as  examples. 

Cell-parasites.  There  are  a  large  number  of  microscopic 
algal-fungi  of  very  curious  behavior.  Some  of  them  find  their 
way  into  the  skin-cells  of  flowering  plants  and  there  live  as  para- 
sites, while  others  insinuate  themselves  into  the  eggs  of  algae 
and  devour  them.  Some  of  them  are  found  in  the  soft  sub- 
stance of  swamp  plants ;  some  may  be  discovered  in  pond-scum 
filaments  where  they  consume  the  cell-contents ;  some  find  their 
way  into  desmid  cells  and  destroy  them ;  some  enter  the  pollen- 
grains  of  flowering-plants,  notably  of  the  pines,  and  feed  upon 
the  living  contents.  They  invade  the  diatoms  and  various 
algae ;  they  infect  the  spongy  tissues  of  the  peat-mosses ;  they 
penetrate  the  wall  of  fish-mould  eggs  and  by  their  omnivorous 
habits  impress  it  upon  us  that  no  organism  is  too  small  or  incon- 
spicuous to  escape  its  enemies. 

Fish-moulds.  Related  to  the  fungi  which  sometimes  injure 
their  eggs  are  those  surprising  organisms,  the  fish-moulds,  that 
are  often  found  forming  gray  fur  coats  on  the  bodies  of  dead 
minnows  or  dead  frogs.  They  are  especially  unwelcome  in  fish 
hatcheries  where  they  attack  the  eggs  of  the  fish  and  destroy 
them.  Some  varieties  are  found  upon  the  dead  bodies  of  aquatic 
insects  and  others  grow  upon  decaying  substances  when  sub- 


46  Minnesota  Plant  Life. 

merged  in  the  water,  although  the  majority  are  parasitic  upon 
living  plants  or  animals,  or  make  the  dead  bodies  of  these  their 
habitat.  The  life  of  a  fish-mould  differs  from  that  of  the  black 
mould  in  some  important  particulars  from  its  being  an  aquatic 
organism.  Its  spores  are  not  mere  passive  spheres  of  micro- 
scopic size  like  those  of  the  black  mould,  but  are  provided  with 
swimming  lashes,  so  that  they  may  propel  themselves  through 
the  water  in  search  of  other  fish  or  insects  upon  the  bodies  of 
which  they  may  be  fortunate  enough  to  obtain  a  lodgment.  One 
fungus  related  to  the  fish-moulds,  not  yet  discovered  in  Minne- 
sota, but  possibly  occurring  somewhere  within  the  state,  is 
noteworthy  in  botanical  annals  as  being  the  only  fungus  known 
to  produce  motile  spermatozoids  like  those  of  the  algae  and,  as 
will  be  seen  later,  of  the  ferns  and  mosses. 

Mildews.  Closely  related  to  the  fish-moulds  are  the  mildews. 
These  are  fungi  which  live  as  parasites  upon  land  plants.  A 
striking  example  of  the  group  is  the  mildew  of  mustards,  which 
occasions  a  rotting  of  the  stems  and  leaves  in  the  shepherd's- 
purse.  Another  causes  a  rotting  of  potato  tops  and  is  one  of  the 
most  serious  diseases  of  the  potato  with  which  cultivators  have 
to  contend.  Still  another  which  occurs  in  Minnesota  is  the 
mildew  of  the  grape-vines,  inducing  the  leaves  to  wither  and 
decay.  The  lives  of  mildews  are  in  many  respects  similar  to 
those  of  the  fish-moulds,  but  with  certain  differences  owing  to 
their  non-aquatic  habits.  For  example,  the  mildew  of  the  vine 
when  it  attacks  the  leaves  goes  about  the  task  somewhat  in  this 
fashion.  From  the  air,  into  which  from  other  mildewed  leaves 
the  spores  have  been  projected,  certain  spores  come  to  fall  upon 
the  surface  of  a  healthy  leaf.  They  lie  upon  the  skin  of  the  leaf 
and  extend  little  infecting  tubes  which  crawl  around  upon  the 
surface  of  the  leaf  until  they  find  one  of  the  air-pores  with  which 
the  leaf  is  provided  for  respiratory  and  vapor-excretory  pur- 
poses of  its  own.  Into  such  apertures  the  fungus  insinuates 
itself,  and  as  its  infection-tube  crawls  beneath  the  skin  of  the 
leaf  among  the  soft  cells  filled  with  leaf-green  and  starch,  it 
finds  there  plenty  of  food  material.  Into  each  cell  it  drives  a 
little  sucking  organ  and  extracts  the  nutritive  substances  and 
converts  them  into  its  own  body.  Going  thus  from  cell  to  cell 
it  finally  saps  the  life  of  so  many  of  them  that  the  usefulness  of 


Minnesota  Plant  Life.  47 

the  leaf  is  destroyed,  and  thus  the  vigor  of  the  whole  vine  is  defi- 
nitely impaired.  When  the  mildew  has  accumulated  in  this 
manner  sufficient  nutriment  for  its  needs  it  puts  forth  a  branch 
which  grows  out  through  one  of  the  air-pores  of  the  leaf  and 
here,  in  the  open  air,  spore  cells  are  formed.  These  are  sepa- 
rated from  the  branch  which  produced  them  and  are  carried 
away  by  wind-currents  to  other  vine  leaves.  Moreover  the  mil- 
dew within  the  tissues  of  the  leaf  breeds  after  its  fashion,  form- 
ing little  spherical  eggs  which  after  they  have  been  fecundated 
divide  up  internally  into  a  considerable  number  of  tiny  motile 
bodies,  provided  with  lashes,  so  that,  when  the  rotting  mass  of 
the  leaf  has  broken  down  after  some  rain,  these  motile  cells  can 
be  washed  out  and  swim  to  fresh  parts  of  the  leaf  or  fall  with 
the  rain  drops  to  other  leaves  upon  the  same  plant.  Such  egg- 
cells  of  the  mildew  serve  to  bridge  over  the  winter  season,  and 
it  is,  therefore,  important,  if  potatoes,  vines,  or  lettuce  should  be 
in  the  habit  of  mildewing,  that  all  dead  leaves  in  the  autumn 
should  be  burned.  This  diminishes  for  the  following  season  the 
danger  from  fresh  infection. 


Chapter  VII. 

Smuts  and  Rusts. 


Higher  fungi.  The  plants  already  described  may  suffice  as 
examples  of  the  algal  fungi.  The  higher  or  "true"  fungi  con- 
stitute a  very  large  group  of  various  forms,  some  of  which  are 
parasitic,  attaching  themselves  to  the  bodies  of  plants  or  of 
animals,  while  others  live  upon  decaying  organic  matter.  No 
fungus  has  leaf-green  and  consequently  no  fungus  can  manu- 
facture starch  out  of  carbonic-acid-gas  and  water,  but  its  nutri- 
tion is  rather  animal-like,  in  that  there  must  be  provided  more 
-complex  food-substances.  A  fungus  cannot  live  on  a  diet  prin- 
cipally of  air,  salts  and  water  as  do  the  algae,  mosses,  ferns  and 
most  flowering  plants. 

Smuts.  Among  the  higher  fungi  the  smuts  are  a  well-known 
group.  Every  one  is  familiar  with  the  smut  of  Indian  corn 
which  occasions  the  appearance  of  great  distorted  kernels,  many 
times  as  large  as  the  ordinary  ones,  composed  almost  entirely 
of  smut  threads  and  a  very  copious  black  mass  of  smut  spores. 
Other  kinds  of  smut  are  found  upon  oats,  upon  wheat,  upon 
millet-grass,  upon  sedges,  and  upon  sand-burrs.  Generally  the 
smut  spore-masses  develop  themselves  in  the  seed-areas  of 
plants,  and  substitute  for  the  seed  their  own  fruit-bodies. 
Hence  the  smut  fruit-body  in  the  Indian  corn  takes  the  form 
of  a  greatly  enlarged  corn  kernel  and  the  stinking  smut  of  wheat 
fills  the  wheat  grain  with  a  mass  of  spores,  allowing  the  wheat 
to  produce  only  the  shell  of  the  fruit  while  the  interior  is  a  solid 
mass  of  smut.  Sometimes  a  whole  flower-cluster  is  infected  as 
in  the  sand-burr  smut.  In  a  few  plants  the  stamens  are  attacked 
by  smut  fungi  and  an  example  is  furnished  by  the  corn-cockle, 
a  weed  belonging  to  the  pink  family  and  to  be  met  with  in  cul- 
tivated fields.  Here  the  stamens,  when  mature,  open  in  the  or- 
dinary way  to  cast  out  their  pollen,  but  if  the  smut  that  some- 


Minnesota  Plant  Life,  49 

times  affects  them  has  gained  a  foothold,  they  might  as  well 
save  themselves  the  trouble,  for  all  the  pollen  grains  will  have 
been  destroyed  and  in  their  place  will  be  the  spores  of  the  smut. 

Peat-moss  smut.  Still  another  kind  of  smut  develops  its 
spores  in  the  capsules  of  the  peat-moss,  and  under  such  condi- 
tions when  the  capsule  opens  to  eject  its  spores  there  are  no 
moss-spores  present,  but  only  the  smaller  black  reproductive  cells 
of  the  smut.  Until  recently  this  condition  of  things  caused  bot- 
anists to  labor  under  a  misappreherlsion  concerning  the  life- 
history  of  the  peat-moss  and  in  most  of  the  books  peat-mosses 
are  described  as  producing  two  kinds  of  spores,  some  large  and 
others  small.  The  supposed  small  spores  of  the  peat-moss  are, 
however,  not  peat-moss  spores  at  all,  but  are  developed  on  a  par- 
asitic plant  which  has  the  interesting  habit  of  forming  them  in 
exactly  the  same  little  round  capsule  which  the  peat-moss  had 
been  to  the  pains  of  developing  for  its  own  spores. 

The  life  of  a  smut.  A  large  number  of  plants  in  Minne- 
sota are  affected  by  smuts  and  sometimes  two  or  more  va- 
rieties will  be  attacked  by  the  same  kind.  More  often,  how- 
ever, the  smuts  which  are  found  on  different  kinds  of  higher 
plants  are  themselves  specifically  distinct.  The  life  of  a  smut 
is  interesting  because  it  is  typical  of  the  manner  in  which  many 
parasitic  fungi  develop.  There  may  be  selected  for  description 
the  stinking  smut  of  wheat.  Inside  the  affected  kernels  clusters 
of  spores  are  formed  which  upon  the  breaking  of  the  kernels, 
during  the  threshing  of  the  wheat  or  while  it  is  being  shovelled 
about  in  bins  or  while  it  is  standing  in  its  head,  are  liberated  and 
fall  upon  the  ends  of  other  uninfected  kernels.  There  they  are 
caught  in  the  little  hairs  which  are  present  at  the  germinal  end, 
and  when  the  wheat  kernel  is  sown  and  germinated  the  smut 
spores  germinate  also  and  their  delicate  threads  grow  in  the  tis- 
sues of  the  wheat  plant  keeping  pace  with  the  host  as  it  extends 
higher  and  higher  into  the  air.  When  the  wheat  flowers  are 
formed  and  the  rudiments  of  the  fruits  begin  to  appear  some 
of  the  smut  filaments  grow  into  the  young  kernels  and,  as  these 
develop,  the  smut  filaments  begin  dividing  themselves  into 
spore-cells,  exerting  a  disintegrating  effect  upon  the  interior  of 
the  kernel,  so  that  finally  one  thus  infected  becomes  filled  with 
thousands  of  spores  of  the  smut.  The  process  may  then  be  re- 
5 


50  Minnesota  Plant  Life, 

peated  and  thus  smut  is  perpetuated  from  year  to  year.  On 
account  of  the  habits  of  the  smut  it  is  a  disease  of  grain  which 
can  be  eradicated  by  the  intelligent  farmer,  if  he  will  take  the 
trouble  to  kill  all  the  smut-spores  which  are  clinging  to  the  hairy 
ends  of  his  seed-wheat  kernels.  This  can  be  done  by  "blue- 
stoning,"  or  by  immersing  the  seed-wheat  for  five  minutes  in  wa- 
ter of  132  degrees  Fahrenheit.  By  such  means  the  vitality  of  the 
smut  spores  is  destroyed,  for  they  are  exposed  at  the  end  of  the 
grain  while  the  wheat  plantlet  itself  inside  the  kernel  is  pro- 
tected by  the  firm  fruit-wall  and  is  not  injured  by  the  poison  or 
by  the  heat.  By  such  methods  if  generally  and  continuously 
employed,  it  would  be  possible  to  terminate  the  enormous  finan- 
cial losses  which  farmers  in  Minnesota  and  the  Northwest  sus- 
tain from  the  various  cereal  smuts. 

Rusts.  Related  to  the  smuts  are  a  variety  of  plants  which 
may  for  convenience  be  grouped  under  the  general  name  of 
rusts.  Of  these  a  great  many  different  kinds  exist  in  Minne- 
sota. They  infest  the  leaves  of  numerous  species  of  plants,  the 
Labrador  tea,  the  pines,  spruces,  and  tamaracks,  the  golden- 
rods,  asters,  thistles,  bellworts  and  poplars,  the  flax,  willows, 
horsemints  and  sunflowers,  the  junipers,  pears,  apples,  beans, 
violets  and  a  great  number  of  others. 

Wheat-rusts.  The  forms  of  greatest  economic  interest  are 
the  three  sorts  of  rusts  which  attack  wheat.  There  are  over 
700  different  kinds  of  rusts  belonging  to  the  wheat-rust  type, 
many  of  which  occur  on  grasses,  but  the  majority  on  numerous 
other  varieties  of  plants.  The  wheat-rusts  are  among  the  most 
remarkable  of  fungi  from  the  singular  custom  which  they  have 
of  changing  periodically  their  habitation  from  wheat  to  other 
plants.  Not  only  do  they  change  their  place  of  abode,  but  they 
change  their  form  and  structure  as  well,  so  that  it  would  be  im- 
possible, unless  one  knew,  to  recognize  the  wheat-rust  after  it 
had  migrated  to  one  of  the  other  plants  upon  which  it  has  ac- 
quired the  habit  of  developing.  The  three  sorts  of  wheat-rust 
which  occur  in  Minnesota  alternate  on  different  plants,  one  de- 
veloping on  barberry  leaves  and  probably  also  on  the  leaves  of 
some  other  species  which  has  not  been  identified,  another  re- 
appearing on  buckthorn  leaves,  and  a  third  on  borage  leaves. 
It  must  be  remembered  that  these  are  three  different  varieties 


Minnesota  Plant  Life. 


FIG.  11.— Patches  of  wheat-rust,  natural 
size  and  enlarged.  The  red  nist  stage. 
After  Atkinson. 


of  wheat-rust.  They  cannot  convert  themselves  into  each  other 
but  are  independent  plants  as  distinctly  as  are  oats  and  rye.  It  is 
well-known  that  there  are  two  stages  of  wheat-rust,  one  of  which 
develops  in  the  early  summer  and  autumn  and  is  known  as  the 
red  rust,  the  other  developing  in  late  summer  and  autumn  and 
known  as  the  black  rust.  The  char- 
acteristic colors  of  the  two  stages 
are  given  by  masses  of  spores  grow- 
ing in  layers  upon  the  plant-body  of 
the  rust  which  in  turn  consists  of  a 
network  of  parasitic  threads  living 
in  the  tissues  of  the  wheat  plant,  the 
skin  of  which  is  burst  by  the  fungus. 
It  is  the  same  plant  body  which 
produces  the  red  spores  forming 
red  streaks  on  the  wheat  leaf  that 
afterwards  produces  black  spores 
in  equally  enormous  numbers  occasioning  the  black  rust  stage. 
The  red  or  "summer"  spores  are  ovoid,  spiny  bodies,  properly 
described  as  single  cells.  Their  walls  are  thinner  than  those 
of  the  black  rust.  The  black,  or  "autumn"  spores  have 

smooth  walls  and  are  divided  into  two 
cells  by  a  cross  partition  situated  near 
the  centre  of  the  somewhat  elongated 
and  pointed  or  rounded  body.  Red- 
rust  spores,  when  separated  from  their 
stalks  by  the  wind,  may  be  carried 
throughout  the  summer  to  other 
wheat  plants,  and  thus  the  infection 
spreads  possibly  over  a  whole  field. 
The  black-rust  spores  remain  dor- 
mant during  the  winter  upon  the  stub- 
ble and  debris  of  the  field.  In  the 
spring  each  of  the  two  cells  of  the 
black-rust  spore  develops  a  tiny  jointed  body  upon  which  four 
very  small  thin-walled,  colorless  spore-cells  are  produced.  Now 
is  the  time  selected  by  the  wheat-rust  for  the  periodic  change  of 
habitation.  It  is  known  that  the  small  spores  thus  produced 
do  not  so  readily  germinate  if  blown  upon  wheat  plants,  but 


FIG.  12.— Patches  of  wheat-rust,  nat- 
ural size  and  enlarged.  The  black 
rust  stage.  After  Atkinson. 


Minnesota  Plant  Life. 


may  find  their  way  to  the  leaves  of  the  barberry.  When  they  fall 
upon  the  epidermis  of  such  leaves  they  develop  infection  tubes, 
penetrate  the  skin  and  form  a  filamentous  plant  body  within 
the  soft  inner  tissues.  At  their  time  of  fruiting  they  form  two 
sorts  of  fruits,  one  upon  the  under  side  of  the  barberry  leaves, 
known  as  cluster  cups,  the  other,  peculiar  bottle-shaped  fruits, 
upon  the  upper  side.  In  the  cup-shaped  fruits  large  numbers 
of  spherical  orange-colored  spores  are  produced  which  if  blown 
away  to  a  wheat  field  will  infect  the  wheat.  In  the  bottle- 
shaped  fruits  smaller  elongated  spores  are  formed,  but  it  is  not 
known  how  these  germinate  nor  what  becomes  of  them  in  the 
natural  order  of  events.  Barberries  are  by 
no  means  abundant  in  Minnesota,  only  a  few 
of  them  existing  in  hedge  rows,  and  while  it 
is  by  no  means  inconceivable  or  absurd,  on 
account  of  the  winds  which  blow  over  the 
wheatfields  of  the  Northwest,  to  suppose  that 
barberries  in  the  east  might  infect  the  wheat 
in  Minnesota  or  the  Dakotas,  yet  it  is  more 
probable,  I  think,  that  the  wheat-rust  passes 

its  cluster-cup  stage 
on  some  common 
Minnesota  plant 
which  has  not  yet 
been  identified  as 
maintaining  this 
particular  kind  of 
rust,  or  that  it  omits 
altogether  its  cus- 
tomary migrations 
to  other  plants. 
It  is  apparent  that  such  a  disease  as  the  rust  offers  difficulties 
to  the  economic  farmer  desirous  of  protecting  his  crop,  far  in 
excess  of  those  presented  by  the  smut,  for  while  smut  spores 
caught  in  the  ends  of  the  wheat  kernels  can  be  killed  there  by 
hot  water,  no  practicable  method  exists  of  policing  the  atmos- 
phere and  preventing  rust  spores  from  finding  their  way  to  the 
young  wheat.  Therefore,  the  most  feasible  plan  for  combatting 
wheat  rust  is  by  the  development  of  so-called  "rust  proof"  va- 


FiG.  13. — Wheat-rust  in  its  barberry -leaf  stage;  to  the  left  a 
barberry  leaf  with  diseased  spots;  in  the  middle,  a  sin- 
gle spot  with  cups;  to  the  right,  two  of  the  cups,  in  top 
view  slightly  magnified.  After  Atkinson. 


Minnesota  Plant  Life. 


53 


rieties.     While  smut  is,  upon  the  whole,  the  easiest  of  the  wheat- 
diseases  to  control,  rust  is  the  most  difficult. 

The  remarkable  migratory  habit  of  the  wheat-rust  and  its 
allies  coupled  with  the  extraordinary  change  in  form  which  the 
fungus  assumes  upon  the  different  habitats  gives  rise  to  some 
very  surprising  conditions  in  rust  life-histories.  For  after  the 
migratory  habit  had  been  formed  it  would  appear  that  some- 
times one  or  the  other  of  the  phases  became  extinct,  so  there 
are  varieties  of  rusts  which  exist  only  in  the  cluster-cup  phase, 


FIG.  14.— Magnified  section  through  a  cluster-cup  of  the  wheat-rust  in  its  barberry-leaf  stage. 
Shows  chains  of  spore-cells.  The  large  cells  at  the  sides  are  those  of  the  barberry  leaf 
much  magnified.  After  Atkinson. 

and  others  only  in  the  red  and  black-rust  phases.  For  a  long 
time  students  of  the  fungi  thought  that  the  cluster-cups  were 
entirely  different  from  the  rust,  and  it  was  only  because  people 
noticed  more  than  a  century  ago  that  "barberry  bushes,"  as  the 
saying  was,  "blasted  the  wheat,"  that  a  hint  was  given  to  mod^ 
ern  research,  in  consequence  of  which  the  astonishing  behavior 
of  the  rust  fungi  is  now  more  thoroughly  understood. 

Relatives  of  the  wheat-rust.  Among  the  relatives  of  the 
wheat-rust  there  are  some  forms  in  Minnesota  characterized  by 
little  peculiarities  which  enable  botanists  to  classify  them  in  dif- 
ferent genera.  For  example,  the  black-rust  spores  formed  on 


54 


Minnesota  Plant  Life. 


some  blackberries  are  three-celled  instead  of  two-celled,  and  the 
cluster-cup  masses  on  some  gooseberries  are  developed  upon 
protuberant  filament-aggregates.  Perhaps  the  three  most  re- 
markable forms  are  the  pine-knot  fungi  which  form  knots  some- 
times as  large  as  bushel  baskets  upon  the  branches  of  pine  trees, 
the  so-called  "cedar-apples,"  which  occur  as  curious  bunches, 
the  size  of  one's  thumb  and  armed  with  orange  horns,  on  the 
junipers,  and  the  witch's  brooms  on  balsam  trees.  These  latter 
are  immense,  disordered  tangles  of  branchlets  forming  masses 
sometimes  several  feet  in  diameter.  The  disordered  branching 
is  caused  by  the  growth  of  a  rust-fungus  of  the  cluster-cup  sort 
in  the  substance  of  the  twigs.  When  this  fungus  fruits  it  pro- 
duces its  reproductive  structures  upon  the  leaves  of  the  balsams, 
where  they  recall  strikingly  the  rust  produced  on  barberry 
leaves.  The  witch's  broom  is  a  notable  object  in  the  swamps 
of  Minnesota.  When  large  ones  are  developed  on  the  balsam 
trees  they  look  like  great  crows'  nests  up  in  the  branches  and 
very  often  birds  and  animals  use  the  thick  tangle  of  twigs  to 
conceal  their  own  dwelling  places.  On  the  spruce  trees  there 
is  a  similar  tangle  of  branches  produced  by  the  agency  of  insects, 
but  there  is  of  course  no  development  of  the  characteristic  clus- 
ter-cup fruit-bodies  upon  the  leaves.  The  related  pine-knot 
fungus  does  not  commonly  fruit  every  year,  but  sometimes  the 
whole  surface  of  the  knot  will  be  found  covered  with  the  little 
orange  pustules  of  the  rust. 


Chapter  VIII. 

Trembling  Fungi,  Club-fungi,  Shelf-fungi  and  Mushrooms, 


Trembling  fungi.  Somewhat  related  to  the  rusts,  although 
one  would  hardly  suppose  it  from  their  appearance,  are  the  sin- 
gular gelatinous  yellow  or  pink  wrinkled  masses  which  are  often 
found  upon  decaying  logs  in  shady  places.  These  cannot  be 
mistaken  for  the  plant-bodies  of  slime-moulds,  because  they  are 
of  a  firmer  cartilaginous  texture.  They  are  capable  of  produc- 
ing over  their  surface  a  layer  of  spores  which  when  separated  by 
the  wind  or  rains  may  propagate  them  upon  other  suitable  sub- 
strata. From  their  tremulous  character  these  plants  are  some- 
times called  "trembling  fungi."  Rather  more  highly  organized 
but  in  the  same  general  order  of  development  are  the  leather- 
like  gray  skins  which  are  often  found  upon  the  under  sides  of 
decaying  twigs.  Related  forms  are  sometimes  provided  with 
little  stalks  and  grow  up  cornucopia-like  from  the  bark. 

Club  fungi.  Another  family  of  fungi  which  includes  forms 
not  so  very  different  from  these  skin-fungi,  comprises  also  those 
which  stand  up  on  the  forest-mould  like  little  yellow  Indian- 
clubs,  an  inch  or  two  in  height.  The  upper  end  of  such  club- 
fungi  is  swollen,  and  it  is  there  that  the  spore-bodies  are  partic- 
ularly developed.  Not  all  of  the  club-fungi  are  unbranched; 
but  some  of  them  are  divided  like  the  antlers  of  a  deer,  and  yet 
others  in  which  the  branching  is  more  copious  grow  in  pearl- 
gray,  yellow,  white  or  pinkish  tufts,  several  inches  high,  and 
covering  spaces  as  large  as  a  dinner  plate.  They  may  be  rec- 
ognized by  the  generally  erect  habit  of  all  the  branches,  so  that 
their  forms  remind  one  of  the  branching  of  certain  night-bloom- 
ing cereuses  of  the  New  Mexican  desert.  Commonly  the 
branches  are  more  or  less  cylindrical  and  blunt,  but  one  form, 
which  is  not  uncommon  in  hard-wood  forests  along  river  bot- 
toms in  the  southern  part  of  the  state,  has  all  its  branches 


56  Minnesota  Plant  Life. 

shaped  somewhat  like  clam  shells,  so  that  the  whole  plant-body, 
often  several  inches  in  diameter,  seems  to  be  composed  of  nu- 
merous white  shells  overlapping  each  other  and  all  attached  to 
a  common  base. 

Prickle-fungi.  The  prickle-fungi — at  least  some  of  them — 
might  be  mistaken  for  much  branched  forms  of  club-fungi ;  but 
they  can  be  distinguished  by  the  general  downward  tendency 
of  the  branches,  so  that  in  a  well-known  species  not  uncommon 
in  the  valley  of  the  St.  Croix  where  it  grows  upon  decaying  tree- 
trunks,  there  is  a  coral-like  aspect  to  the  whole  plant-body. 
This  variety  is  generally  white,  or  slightly  yellowish,  or  yellow- 

HHHHHH||HHHHH||I  WHHHHHBnHHHHMHMaHH^ 

*    , 


»     ., 


FIG.  15.— Growth  of  club-fungi  on  decaying  wood.     After  Iyloyd. 

ish-brown  in  color,  often  as  large  as  a  man's  head,  and  made  up 
of  a  group  of  thick,  irregular  branches  upon  the  under  sides  of 
which  great  numbers  of  prickles  half  on  inch  or  more  in  length 
grow  downward.  Not  all  of  the  prickle  fungi  have  exactly  this 
kind  of  a  plant-body.  Some  of  them  outwardly  resemble  toad- 
stools, and  might  be  mistaken  for  them  if  one  did  not  look  upon 
the  under  side  where  he  would  discover  instead  of  the  radiating 
gills  of  the  toadstool  the  whole  under  surface  of  the  cap  cov- 
ered with  a  growth  of  prickles.  Upon  the  surface  of  these 
prickles  the  spores  of  the  plant  are  developed,  and  by  their  co- 
operation the  fungus  is  able  to  maintain  itself  from  year  to  year. 


Minnesota  Plant  Life. 


57 


In  these  forms,  however,  and  in  many  of  those  to  follow,  the 
conspicuous  part  of  the  plant  is  really  nothing  more  than  its 
highly  developed  fruit-body,  while  the  vegetative  portion  con- 
sisting of  a  spongy  or  cottony  substance  lies  imbedded  in  the 
decaying  timber. 

Shelf-fungi.  Related  to  the  prickle-fungi  are  the  well-known 
pore-fungi,  or  shelf-fungi,  which  are  such  familiar  objects  in  the 
woods  of  Minnesota.  Often  they  seem  to  be  growing  upon  liv- 
ing trees,  but  it  will  be  found  upon  examination  that  they  have 


FIG.  16.— Shelf-fungus  growing  on  dead  stump  of  oak  tree.     After  photograph  by  Hibbard. 

attacked  some  wounded  or  dead  portion  of  the  trunk,  for  these 
fungi  are  none  of  them  truly  parasitic.  They  are  more  com- 
mon, indeed,  upon  dead  timber,  either  prostrate  or  standing. 
Very  pretty  examples  of  shelf-fungi  are  abundant  upon  the 
birch-trees  of  Minnesota,  and  this  particular  species  is  known 
as  the  birch-tree  pore-fungus.  The  fruit-bodies  hang  down 
somewhat  like  bells,  are  of  a  white  color,  not  \voody  but  with 
much  the  consistency  of.  punk  or  cork.  They  grow  larger  from 
year  to  year,  the  new  growth  covering  that  of  former  summers, 
and  every  season  a  new  layer  of  pores  is  produced  upon  the 


58  Minnesota  Plant  Life. 

under  side.  In  the  Minnesota  woods  there  are  a  great  number 
of  different  kinds  of  pore-fungi  which  show  characteristic  dif- 
ferences of  shape,  size,  thickness,  color,  texture,  and  endurance. 
One  of  them,  called  the  sulphur-colored  pore-fungus,  which 
grows  in  very  large  masses  is  edible  when  young,  but  the  great 
majority  of  them  while  not  poisonous,  are  too  tough,  leathery 
and  woody  to  be  very  appetizing.  Some  of  them,  indeed,  no- 
tably the  great  shelves  a  foot  or  more  across  which  occur  upon 
oak  trees,  are  almost  as  solid  as  the  wood  of  the  tree  itself. 

Upon  one  occasion  I  noticed  that  in  the  pores  of  the  under 
side  of  one  of  these  fungi,  a  large  number  of  mosquitoes  had 
been  caught  by  their  legs  and  had  afterwards  been  covered  by 
a  growth  of  cottony  filaments  of  the  fungus,  and  I  wondered 
whether  the  plant  might  not  derive  some  benefit  from  its  ap- 
parent capture  of  insects  and  digestion  of  their  bodies.  It  is 
not  at  all  clear,  however,  that  such  a  fungus  should  be  included 
in  the  great  category  of  flesh-eating  plants,  because  it  is  a  com- 
mon habit  of  the  fruit-body  to  inclose  small  objects  which 
chance  to  be  in  its  way.  Sometimes  when  these  shelf-fungi 
grow  near  the  ground  they  will  be  found  with  grass  leaves  pen- 
etrating them  and  in  such  cases  it  is  not  to  be  supposed  that  the 
grass  leaf  has  grown  through  the  fungus,  but  rather  that  the 
fungus  has  grown  around  and  has  enclosed  the  leaf. 

The  pores  of  these  interesting  fungi  are  of  different  sizes  and 
shapes.  In  some  varieties  they  are  almost  invisible,  they  are 
so  small.  Other  sorts  have  the  pores  much  larger.  In  some 
the  pores  are  circular,  in  others  they  are  hexagonal  or  irregular 
in  shape.  In  one  kind  which  is  common  upon  willows,  form- 
ing fruit-bodies  not  more  than  two  or  three  inches  across,  the 
pores  are  labyrinthine  in  shape,  like  the  passages  in  the  puzzle- 
gardens  which  are  sometimes  laid  out  in  parks.  There  is  con- 
siderable difference  too  in  the  upper  surface  of  pore-fungi. 
Some  of  them  are  white  and  smooth  as  in  the  birch-tree  form, 
while  others  are  fuzzy.  Some  are  hard  and  marked  by  annual 
rings  showing  where  the  growth  of  each  year  has  jutted  out 
beyond  the  growth  of  the  previous  year.  Some  are  sticky,  but 
rarely  slimy  in  texture ;  some  are  cartilaginous  or  horny  to  the 
touch,  and  many  are  spongy  and  soft. 


Minnesota  Plant  Life. 


59 


Different  genera  of  shelf-fungi  are  established  by  botanists, 
principally  upon  the  character  of  the  pores.  A  genus  which 
contains  numerous  highly  poisonous  species,  is  recognized  by 
the  readiness  with  which  the  pore-layer  can  be  separated  from 
the  under  side  of  the  sterile  portion  of  the  fruit-body.  One  va- 
riety of  these  poisonous  fungi  is  abundant  in  tamarack  swamps 
throughout  the  state.  The  general  shape  of  the  plant  is  quite 
exactly  like  that  of  a  toad-stool,  a  short  thick  stem  rises  from 
the  ground,  and  on  top  of  this  a  red  cap  is  borne,  from  two  to 


Pic,.  17. — Upper  and  under  sides  of  mushroom-like  pore-fungus.    After  I_loyd. 

five  or  even  more  inches  in  diameter.  The  top  is  of  a  dull  crim- 
son or  maroon-red  tint,  with  scale-like  markings  resembling  a 
serpent's  skin.  Upon  the  under  side  will  be  seen  a  layer  of 
large  yellowish  pores,  separated  from  each  other  by  thin  parti- 
tion walls  in  which  the  coloring  substance  is  developed.  If 
one  pulls  off  the  cap  of  this  fungus  and  breaks  it  in  two  he 
will  find  that  the  whole  layer  of  pores  is  very  easily  peeled 
away  from  the  rest  of  the  cap.  Suppose  now  that  one  of 
these  pores  was  magnified  until  it  was  as  large  as  an  ordinary 


6o 


Minnesota  Plant  Life. 


well.  Then  if  one  could 
enter  it  he  would  see 
the  whole  wall  covered 
with  ovoid  spores,  now 
apparently  as  large  as  ap- 
ples. Since  the  pores  all 
open  downwards  it  is  easy 
to  see  that  if  the  spores 
fall  from  their  supports 
they  will  gradually  if  not 
immediately  tumble  out 
through  the  opening  and 
may  then  be  distributed 
by  wind  or  water.  It  is 
altogether  best  never  to 
eat  any  kind  of  a  pore- 
fungus  in  which  the  pore- 
layer  is  readily  separable 
from  the  rest  of  the  fruit- 
body,  although  there  are 
a  few  harmless  varieties 
even  in  this  generally 
dangerous  group. 

Some  shelf-fungi  are 
not  truly  pore-fungi,  but 
the  under  side  is  perfectly 
smooth  or  marked  at  best 
with  1  o  w,  longitudinal 
wrinkles.  These  may,  per- 
haps, be  considered  as 
forms  in  which  the  pores 
have  either  not  yet  come 
to  develop,  or  as  varieties 
in  which  for  some  reason 
the  pores  have  become 
shallower  until  finally 
they  have  been  com- 
pletely lost. 


FIG.  18. — A  pore-fungus  lying  flat 
upon  a  decaying  branch.  After 
lyloyd. 


Minnesota  Plant  Life. 


61 


Mushrooms  and  toadstools.  Related  to  the  pore-fungi,  and 
especially  to  those  in  which  the  pores  are  elongated  or  laby- 
rinthine, are  the  well-known  mushrooms  and  toadstools.  There 
is  little  systematic  difference  between  mushrooms  and  toad- 
stools. People  are  in  the  habit  of  calling  an  edible  toadstool  a 
mushroom,  and  a  poisonous  mushroom  a  toadstool.  The  fact 
is  that  some  of  the  species 
of  the  great  mushroom  ge- 
nus are  edible  while  others 
are  not,  and  it  is  often  ex- 
tremely difficult  even  for  an 
expert  to  distinguish  be- 
tween edible  and  poisonous 
varieties.  The  following  are 
very  good  rules  to  follow  if 
one  feels  an  uncontrollable 
inclination  to  experiment 
with  mushrooms  as  an  arti- 
cle of  diet : 

Never  eat  a  mushroom 
that  is  highly  colored. 

Never  eat  a  mushroom 
that  has  pink  gills. 

Never  eat  a  mushroom 
that  seems  to  grow  out  of  a 
little  cup  at  the  base. 

Never  eat  a  mushroom 
that  has  a  milky  juice. 

Never  eat  a  mushroom 
that  changes  color  shortly 
after  its  substance  is  broken. 

Never  eat  a  mushroom 
with  a  pungent  odor. 

Never  eat  a  mushroom  with  a  sticky  or  slimy  cap. 

Never  eat  an  immature  mushroom  unless  absolutely  certain 
what  sort  of  a  form  it  will  be  when  mature. 

None  of  these  rules  is  absolute.  There  are  exceptions  to  all 
of  them,  to  some  more  than  to  others,  but,  together,  they  con- 
stitute a  safe  code  and  one  cannot  go  far  wrong  in  observing  it. 


FIG.  19.— Deadly  variety  of  mushroom.'  After 
Atkinson.  Bulletin  138,  Cornell  Ag.  Exp. 
vStation.  This  is  sometimes  known  as  the 
"poison  cup." 


62  Minnesota  Plant  Life. 

Yet  a  single  rule,  which  I  believe  to  be  the  best,  is  to  eat  no 
mushrooms  of  any  sort  unless  quite  sure  that  they  are  edible,  for 
some  of  the  deadliest  poisons  known  to  students  of  plant  chem- 
istry are  contained  in  the  plants  of  this  genus.  One  in  partic- 
ular, which  grows  from  a  little  cup  at  the  base  and  spreads  out 
a  rather  thin  cap  is  so  fatal  that  a  small  portion  of  it  is  sufficient 
to  cause  death.  Still  on  the  other  hand,  it  is  true  that  a  great 
many  edible  species  are  to  be  obtained  in  the  woods  and  fields 
of  Minnesota,  and  it  seems  a  pity  that  such  excellent  food  should 
go  to  waste  when  there  are  many  people  who  would  be  glad  to 
avail  themselves  of  this  form  of  nature's  bounty. 


FIG.  20. — Under  side  of  two  mushroom-fruits.    After  Atkinson.     Bull.  138,  Cornell  Ag.  Exp. 

Station. 

All  true  mushrooms  are  characterized  by  the  presence  on  the 
under  side  of  the  cap,  of  radiating  gills  or  plates,  hanging  down 
like  the  ornamental  tissue-paper  decorations  which  are  fancied 
by  proprietors  of  butchers'  shops.  Except  for  this  general  char- 
acter their  forms  are  various  and  some  of  them  with  long  slender 
stalks  and  thin  conical  or  expanded  caps  present  a  very  different 
appearance  from  those  with  short,  massive  stalks  and  broad 
hemispherical  caps.  A  few  are  devoid  of  definite  stalks  and 
protrude  sideways  from  dead  logs  recalling  quite  exactly  the 
shelf-fungi  in  their  general  habit  of  growth.  The  largest  mush- 
rooms are  found  in  pastures  and  along  roadsides,  lifting  them- 


Minnesota  Plant  Life.  63 

selves  sometimes  nearly  a  foot  into  the  air,  and  provided  with 
basin-shaped  caps,  six  inches  or  more  in  diameter.  Another 
overgrown  form  is  common  on  decaying  timber  and  has  no 
central  stalk  but  stands  out  somewhat  like  a  bracket-shelf. 

Deliquescent  mushrooms.  Not  all  of  the  fungi  with  radiat- 
ing gills  on  the  under  side  are  classed  by  botanists  as  true  mush- 
rooms. One  sort,  which  comes  up  in  the  autumn,  late  in  Sep- 
tember or  in  October,  oozes  into  a  black  and  filthy  slime  as  it 
matures.  When  young  the  fruit-body  is  elongated,  an  inch  or 
so  in  diameter,  sometimes  four  inches  in  length,  white  in  color, 
with  blackish  scale  markings.  In  its  early  stages  when  properly 


FIG.  21.— Common  edible  mushroom.     After  Atkinson.     Bull.  138,  Cornell  Ag.  Exp.  Station. 

cooked  this  is  one  of  the  most  delicious  of  edible  fungi;  but 
after  it  has  begun  to  decay  it  is  neither  appetizing  nor  healthful. 
The  habit  that  these  mushroom-like  fungi  have  of  decaying  is 
a  device  for  scattering  their  spores.  They  are  visited  by  insects 
and  the  spores  are  picked  up  in  the  general  slime  to  which  their 
presence  gives  the  black  color,  and  are  then  carried  away  to  be 
deposited  elsewhere. 

Miniature  mushrooms.  Another  relative  of  the  true  mush- 
room is  a  very  delicate  little  plant  an  inch  or  less  in  height 
growing  upon  decaying  leaves  in  the  forest  or  in  wooded  ra- 
vines. It  has  a  shiny  black  cartilaginous  stem  like  that  of  the 
maiden-hair  fern  and  upon  the  top  of  this  a  white  cap  displays 


Minnesota  Plant  Life. 


a  small  number  of  loosely  arranged  gills  on  the  under  side.    The 
diameter  of  the  cap  is  often  no  more  than  one-eighth  of  an  inch. 


P  c 
I  .2 


Milk  mushrooms.  Still  another  close  relative  of  the  mush- 
room is  the  milk-mushroom.  The  various  species  of  this  genus 
are  supplied  with  a  milky  juice,  white  or  variously  colored, 


Minnesota  Plant  Life.  65 

which  oozes  out  if  the  flesh,  is  broken.  One  kind  with  bluish 
gills  and  juice,  gives  off,  when  broken,  a  distinctive  odor  some- 
thing like  that  of  prussic  acid  and  is  very  deadly.  It  is  not  un- 
common under  white  pine  trees  in  the  northern  part  of  the  state. 

A  considerable  difference  in  durability  exists  among  the 
mushrooms  and  their  near  relatives.  Some  of  them  are  delicate 
and  watery  in  texture,  lasting  but  a  few  hours  after  they  are 
mature.  Others  are  spongy,  or  of  a  texture  like  punk,  while 
those  found  for  example  on  railway  ties  become  hard  and  woody 
even  before  they  are  altogether  mature. 

The  true  mushrooms  are  classified  into  five  principal  groups, 
depending  upon  the  color  of  the  spores,  i.  Forms  with  black 
spores.  2.  Forms  with  dark-brown  spores.  3.  Forms  with 
brown  spores.  4.  Forms  with  red  or  reddish-yellow  spores. 
5.  Forms  with  white  spores.  Among  the  dark-brown  spored 
forms  are  a  number  of  edible  species.  Here  is  included  the  or- 
dinary edible  mushroom  which  is  cultivated  for  the  market. 

It  is  an  easy  matter  to  determine  the  exact  color  of  mush-: 
room  spores  by  cutting  off  the  cap  close  to  the  stem  and  laying 
it  down  on  a  piece  of  paper  with  the  gills  towards  the  paper. 
Within  a  few  hours  hundreds  of  thousands  of  spores  will  -fall  to 
the  paper,  tracing  there  the  gill-arrangement  and  demonstrating 
the  precise  color  of  the  spores.  If  with  the  point  of  a  pen-knife 
a  few  thousands  of  these  spores  be  lifted  and  placed  under  a 
microscope,  they  will  be  found  to  be  somewhat  egg-shaped  or 
spherical  cells  usually  with  smooth  walls  and  provided  each  with 
a  bit  of  living  substance  in  the  interior.  They  are  produced  in ' 
clusters  of  four  all  over  the  surface  of  the  gills.  The  gills  them- 
selves are  made  up  of  interlaced  threads,  which,  when  they  come 
to  the  surface  turn  and  grow  perpendicular  to  it.  Some  of  the 
threads  expand  their  ends,  upon  which  four  little  ears  are  pro- 
duced. The  tip  of  each  of  these  bulges  out  into  a  tiny  egg- 
shaped  spore.  A  very  narrow  neck  connects  each  spore  with 
its  stalk  and  when  ripe  the  spore  drops  off  of  itself. 


Chapter  IX. 

Carrion-fungi  and  Puff-balls* 


Carrion-fungi.  Another  group  of  fungi  not  very  closely  re- 
lated to  the  mushrooms  but  properly  to  be  considered  at  this 
point  includes  the  stinkhorns  or  carrion-fungi.  These  are  among 
the  most  remarkable  of  all  plants.  During  summer  and  au- 
tumn they  spring  up  in  door  yards  from  a  subterranean  vege- 
tative body  which  resembles  a  tangled  mass  of  white  rootlets. 
Upon  some  of  these  rootlets  little  knobs  the  size  of  a  pin  head 
will  be  found  to  arise  just  as  in  mushrooms.  These  grow  rap- 
idly until  they  become  almost  as  large  as  hens'  eggs,  when  sud- 
denly the  top  of  an  egg  is  burst  by  the  pressure  of  the  grow- 
ing parts  within  and  in  a  surprisingly  short  time  there  is  pushed 
out  a  cylindrical  stalk — appearing  very  much  as  if  it  had  been 
cut  out  of  a  loaf  of  bread,  for  it  has  the  peculiar  spongy  texture 
of  the  well-raised  loaf.  This  stalk  is  hollow  and  upon  its  top  is 
borne  a  wrinkled  cap  perforated  in  the  middle  by  an  aperture. 
The  surface  of  the  wrinkled  cap  is  covered  with  a  slimy  green- 
ish-black mass  of  spores  and  mucilage.  Once  seen  this  plant 
will  never  be  forgotten.  It  may  perhaps  be  described  picto- 
rially  as  a  vegetable  confidence-game,  for  if  there  were  any  im- 
moral plants  certainly  this  would  be  one.  It  has  almost  pre- 
cisely the  odor  of  carrion  and  upon  such  an  imitation  of  decay- 
ing flesh  it  bases  its  extraordinary  method  of  distributing  its 
spores.  Attracted  and  deceived  by  the  stench,  various  flies  and 
burying  beetles  visit  it  and  walk  upon  it  apparently  believing  it 
to  be  what  its  odor  indicates.  They  are  even  said  to  lay  eggs 
upon  it  and  to  withdraw  feeling  no  doubt  that  they  have  made 
that  due  provision  for  their  young  which  their  parental  instincts 
suggest.  During  their  investigations,  however,  they  have  in- 
advertently covered  themselves  with  the  sticky  slime  of  the  cap 
in  which  the  spores  of  the  plant  are  embedded  and  these  they 


Minnesota  Plant  Life.  67 

carry  away  and  distribute,  thus  performing  a  work  for  the  plant. 
But  in  a  few  hours  the  whole  fruit-body  decays  and  the  eggs, 
if  any  had  been  entrusted  to  it  under  the  apparently  mistaken 
notion  that  it  would  be  a  good  place  for  maggots  to  develop, 
all  miserably  perish.  There  seems  to  be  no  other  way  to 
describe  such  behavior  except  as  obtaining  service  from  the  in- 
sect under  false  pretences,  and  if  plants  were  really  respon- 
sible creatures  these  carrion-fungi  would  doubtless  find  them- 
selves in  some  plant-penitentiary. 

Even  more  remarkable  is  the  behavior  of  a  Brazilian  relative 
of  the  stinkhorn,  which,  in  addition  to  all  the  devices  that  are 
employed  by  the  Minnesota  species,  adds  a  conspicuous  white 
veil,  hanging  down  from  the  cap  around  the  stalk.  The  veil 
is  reported  by  travelers  to  be  faintly  phosphorescent  at  night 
and,  if  so,  adds  to  the  attractive  influence  which  the  plant  might 
have  upon  night-flying  insects.  There  are  several  species  of 
stinkhorns  in  the  northern  United  States,  but  up  to  the  present 
time  I  have  seen  only  three  in  Minnesota,  one  of  which  has  a 
veil.  It  is  quite  certain,  however,  that  others  occur.  The  only 
way  of  eradicating  them  from  a  lawn,  where  they  are  offensive 
objects  if  produced  in  large  numbers,  is  to  dig  up  carefully  and 
remove  the  underground  portion,  for  if  this  is  not  done  the 
plant  will  offer  its  repulsive  fruits  year  after  year. 

Truffle  puff-balls.  Some  plants,  not  very  distant  relatives 
of  the  carrion  fungus,  produce  their  fruit-bodies  entirely  under- 
ground. Such  forms  may  be  described  as  subterranean  puff- 
balls.  They  are  not  unlike  the  well-known  truffle  of  the  mar- 
kets in  outward  appearance,  but  are  widely  different  in  struc- 
ture. A  few  of  them  have  been  found  growing  in  Minnesota 
woods.  Dogs  or  pigs  can  be  trained  to  dig  them,  finding  them 
by  their  odor,  and,  indeed,  this  is  the  method  which  is  used  by 
truffle-hunters  in  the  woods  of  Europe. 

Puff-balls.  More  familiar  by  far  to  the  ordinary  observer 
than  these  underground  forms  are  the  puff-balls  which  are  so 
common  in  fields,  pastures,  woods  and  meadows  throughout 
the  state.  A  very  considerable  number  of  varieties  of  puff- 
balls  may  be  found  by  any  one  who  looks  for  them  and  is  a  close 
observer.  One  variety  abundant  in  plowed  fields,  where  it  grows 
among  the  stubble  after  a  corn  or  wheat  crop  has  ripened, 


68 


Minnesota  Plant  Life. 


is  the  stalked  puff-ball.  This  plant  is  distinguished  by  a  gray 
stalk  a  quarter  of  an  inch  in  diameter  and  two  or  three  inches 
high.  At  its  top  is  developed  a  little  flattened  spherical  blad- 
der, perforate  in  the  middle,  within  which  are  innumerable 
brown  spores.  If  the  skin  is  squeezed  the  spores  puff  out  at 
the  top  like  so  much  brown  smoke,  hence  the  common  name, 
puff-ball,  which  is  applied  to  this  plant  and  its  relatives. 

Other  puff-balls  have  not  the  same  slender  stalk  that  has  just 
been  described.  Several  kinds  are  more  or  less  pear-shaped, 
standing  with  the  small  end  downward  and  variously  marked 
in  the  different  species.  One  variety  is  nearly  smooth  while 
another  is  covered  with  ._, 

tiny  warts  of  different 
sizes,  sometimes  arranged 
in  patterns  over  the  sur- 
face. In  others  the  sur- 
face is  spiny  and  some- 
times the  spines  occur  in 
little  clusters,  with  their 
tops  drawn  together  like 
the  stems  of  corn  when 
in  the  shock.  If  one  of 
these  puff-balls  be  cut 
lengthwise  it  will  be  seen 
that  the  lower  part  is 
spongy  in  texture  and 
does  not  produce  spores, 
so  that  this  portion  may  be  regarded  as  a  short,  thick  stem. 
The  upper  portion,  however,  produces  an  abundance  of  spores 
which  are  ejected  through  an  aperture  in  the  ordinary  manner. 

Still  other  puff-balls  have  no  stalks,  but  the  whole  fruit-body 
is  a  bladder  filled  with  spores  and  some  of  the  commonest  of 
all  Minnesota  puff-balls  belong  to  this  division.  They  are 
found  abundantly  in  fields  and  pastures  and,  when  ripe,  are  flat- 
tened dark  purplish  or  plum-colored  bodies  from  a  quarter  of  an 
inch  to  an  inch  in  diameter.  The  whole  inside  of  one  of  these 
fruits  consists  of  a  fluffy  mass  of  spores  and  threads — the  dried- 
up  stems  upon  which  the  spores  develop.  In  the  woods  a  stem- 
less  puff-ball  is  found  of  a  lighter  color,  growing  often  as  large 


FIG.  23.     Warty  puff-ball.     After  I^loyd. 


Minnesota  Plant  Life.  69 

as  a  turkey's  egg.  Both  this  and  its  smaller  relative  of  the  pas- 
tures open  somewhat  irregularly  at  the  end  away  from  the 
ground,  or  perhaps  at  the  side.  Among  the  short-stemmed 
puff-balls  two  or  three  large  varieties  are  found ;  one,  the  giant 
puff-ball,  occurs  larger  than  a  man's  head  and  almost  spherical 
in  shape,  while  another  is  in  outline  somewhat  like  a  dinner  bell 
with  the  mouth  closed  and  mound-like. 

Earth-stars.  An  interesting  variety  of  puff-ball  is  the  earth- 
star.  This  has  an  outer  skin  that  splits  radially,  as  one  peels 
an  orange,  revealing  the  inner  skin  that  encloses  the  spores. 
The  little  mouths  of  the  earth-stars  are  nicely  protected  by  a 
group  of  bristles  which,  by  their  sensitiveness  to  moisture,  as- 
sist the  distribution  of  the  spores  under  conditions  which  are 
favorable  for  their  germination. 
Apparently  the  use  to  the  plant  of 
splitting  back  the  outer  skin  is  the 
additional  height  that  it  attains 
from  which  its  spores  can  be  dis- 
tributed. The  points  of  the  sec- 
tions which  have  split  bend  under 
and  lift  the  central  ball  a  half  inch 
or  more  into  the  air,  and  the  spores 
have  an  added  opportunity  of  catch- 
ing some  wind  current,  which,  if 
they  were  closer  to  the  ground,  FlG- 24-  Tufted  Puff-ba11-  After 

Uoyd. 

might  not  distribute  them  so  far. 

Slitted  puff-balls.  A  rather  large  puff-ball  with  a  short  stalk 
and  a  white  egg-shaped  head  is  sometimes  found  in  fields  and 
door  yards,  the  small  end  of  the  egg  pointing  upward  and  the 
large  end  hanging  down  over  the  stalk  which  seems  to  grow  up 
into  a  depression  there.  These  puff-balls  open  by  slits  close 
down  to  the  stalk,  and  the  interior  is  found  to  be  occupied  by 
irregular,  broken,  brown  plates,  radiating  vaguely  from  the 
stalk-region  somewhat  like  the  gills  of  the  mushroom. 

BircTs-nest-fungi.  Among  all  the  puff-balls  few  are  more  in- 
teresting objects  than  the  little  bird's-nest-fungi.  There  are 
three  sorts  of  these  common  in  Minnesota.  None  of  them  is 
very  large  for  they  do  not  exceed  a  quarter  to  a  half  inch  in 
diameter.  They  are  often  seen  growing  on  the  planks  of  old 


70  Minnesota  Plant  Life. 

sidewalks,  in  the  cracks,  or  they  may  be  found  attached  to  twigs 
or  bits  of  decaying  wood.  Each  fruit-body  is  shaped  like  a  vase 
or  bowl,  at  the  bottom  of  which  half  a  dozen  white  or  purple 
egg-like  bodies  are  lying,  so  that  it  has  the  appearance  of  some 
tiny  nest  with  eggs,  hence  the  popular  name  which  has  been 
applied.  If  one  attempts  to  pull  out  the  "eggs"  it  will  be  found 
that  each  of  them  is  flattened  like  two  watch  crystals  placed 
together  and  is  attached  by  a  delicate  cord  growing  from  the 
"nest"  and  fixing  itself  upon  the  middle  of  one  side  of  the  eggs. 
It  must  be  understood  that  the  term  "egg"  as  used  here,  and  as 
used  also  for  the  young  stinkhorns,  should  not  suggest  that  such 
bodies  have  any  of  the  real  meaning  of  an  egg,  since  it  is  applied 
solely  on  account  of  their  shape.  In  the  bird's-nest-fungus  each 
"egg"  is  a  miniature  puff-ball,  with  spores  enclosed  within  its 
membrane,  and  the  whole  bird's-nest-fungus  fruit-body  might 
be  described  as  comparable  to  a  little  group  of  stemless  puff- 
balls  enclosed  in  a  common  vase  or  urn. 

Hard-skinned  puff-balls.  Yet  another  sort  of  puff-ball  is 
readily  distinguished  by  its  hard  nut-like  shell.  Such  plants  are 
called  hard-skinned  puff-balls  and  some  kinds  of  them  grow  to 
be  larger  than  an  ordinary  coffee  cup.  They  are  white  or  brown 
in  color  and  almost  spherical  in  shape.  When  they  open  to  eject 
their  spores  the  whole  top  splits  by  four  or  five  radiating  clefts, 
and  the  sections  of  the  shell  curve  back  from  the  centre  some- 
what as  did  the  outer  skin  of  the  earth-star.  As  they  separate, 
the  fluffy  spores  and  threads  of  the  interior  are  exposed  as  an 
umber  mass  upon  which  the  wind  has  an  opportunity  to  play, 
thus  carrying  off  the  spores  to  other  favorable  regions  for  devel- 
opment. 

Ball-tossing  puff-balls.  In  some  respects  more  remarkable 
than  any  of  the  others  is  the  ball-tossing  puff-ball.  This  is  a 
small  variety,  not  larger  than  an  ordinary  pill,  but  a  little  larger 
than  the  pellets  of  the  homeopathist.  It  occurs  in  clusters  upon 
decaying  wood  and  looks  somewhat  like  slime-mould  fruit  only 
it  has  a  more  leathery  skin,  and  would  be  recognized  upon  close 
observation  to  be  different  from  the  slime-mould  fruits  in  out- 
ward appearance  as  well  as  in  inward  structure.  The  ball-toss- 
ing puff-ball  has  three  layers  of  skin,  one  outside  of  the  other. 
The  two  outer  skins  become  perforate  at  the  end  of  the  ball, 


Minnesota  Plant  Life.  7  i 

exposing  the  third  and  innermost  skin  which  remains  intact. 
The  hole  enlarges  so  that  there  comes  a  moment  when  the  in- 
ner skin  lies  like  a  base  ball  in  a  tea  cup,  surrounded  by  the  two 
outer  skins  which  have  taken  a  vase-like  form.  Very  suddenly 
the  middle  skin  separates  from  the  outer  skin  everywhere  ex- 
cept at  the  edges  and  inverts  itself  with  explosive  force.  It  is 
as  if  the  lining  of  a  porcelain  kettle  should  turn  inside  out.  By 
this  means  the  little  ball  at  the  centre  may  be  projected  several 
inches  into  the  air  as  if  shot  out  of  some  tiny  catapult.  In  this 
way  the  whole  mass  of  spores  enclosed  in  the  inner  skin  is 
thrown  to  some  distance  from  the  point  where  the  parent  plant 
developed,  thus  adding  to  the  favorable  chances  of  the  species 
in  distribution. 


Chapter  X. 

Yeasts,  Morels,  Cup-fungi  and  Truffles* 


All  of  the  higher  fungi  which  have  been  described,  enjoy 
one  character  in  common ;  their  spores  are  produced  upon 
stalks.  No  matter  how  various  the  form  of  the  fruit-body  may 
be,  in  this  one  respect  all  the  different  varieties  agree.  The 
group  of  higher  fungi  now  to  be  considered  is  marked  by  the 
production  of  spores  in  sacs,  hence  they  all  pass  under  the  gen- 
eral name  of  sac-fungi. 

Yeasts.  One  of  the  most  simple  forms  is  the  yeast  plant, 
familiar  to  housewives  and  brewers  the  world  over.  Yeast,  as 
most  people  know,  is  a  culture  of  fungi  developed  upon  malt 
and  hops  and  then  transferred  to  various  substances  for 
purposes  which  differ  in  the  different  arts.  In  bread-making 
the  value  of  the  yeast  lies  in  its  power  of  liberating  carbonic- 
acid-gas  while  it  is  growing  in  the  dough.  When  a  cupful  of 
yeast  is  placed  in  a  baking  of  bread  and  the  dough  is  set  away 
in  a  warm  place  beside  the  stove,  the  yeast-plants  feed  upon  the 
substance  in  the  dough  and  as  they  grow  and  reproduce  they 
create  among  other  waste  products,  carbonic-acid-gas  and  alco- 
hol. When  the  bread  is  kneaded  and  allowed  to  stand  again 
before  placing  in  the  oven,  the  kneading  serves  to  distribute  the 
yeast-plants  evenly  through  the  loaf  and  they  continue  to  grow, 
forming  bubbles  of  gas  and  small  amounts  of  alcohol.  When 
the  lightness  of  the  bread  is  assured  the  loaves  are  placed  in  the 
oven  and  the  heat  which  is  applied  kills  all  the  yeast  plants,  but 
the  bubbles  of  gas  have  done  their  part  in  leavening  the  loaf. 

In  brewing,  it  is  not  the  gas  which  is  deemed  so  desirable, 
but  the  alcohol,  and  the  yeasts  are  permitted  to  develop  until 
the  proper  percentage  of  alcohol  has  been  introduced.  The 
hardening  of  cider,  the  fermentation  of  wine,  and  a  variety  of 
other  processes  are  equally  the  result  of  fungus  growth.  Yeasts 


Minnesota  Plant  Life.  .- 

are  sometimes  impure  or  "bad"  as  the  saying  is.  This  is  owing 
to  the  mixture  with  the  genuine  yeast  of  other  fungal  organ- 
isms, which  liberate  other  and  often  undesirable  substances. 
For  example,  certain  acids  are  produced  through  the  activity  of 
yeast-like  plants,  and  if  such  acid-forming  yeasts  are  present  in 
sufficient  quantity,  the  bread  or  the  beer  becomes  sour.  Hence 
the  cultivation  of  pure  yeast  is  a  prime  necessity  and  when  the 
housewife  or  the  brewer  finds  by  experience  that  yeasts  in  use 
are  no  longer  pure,  a  fresh  supply  must  be  obtained  from  a 
neighbor  or  in  the  market. 

Yeast  is  a  widely  distributed  plant  and  will  often  appear 
as  if  spontaneously,  just  as  black  mould  does  when  a  substance 
suitable  for  its  development  is  exposed  to  the  atmosphere  for  a 
sufficient  length  of  time.     The  yeast-plant  itself  consists  of  thin- 
walled,  egg-shaped  cells  which  have  the  power  of    budding. 
Somewhere  the  wall  bulges  and  the  bulge  enlarges  until  it  is  the 
size  of  the  parent  cell.     Thus  a  branching  body  can  be  built  up, 
but  the  branches  and  buds  readily  separate  from  each  other 
and  in  a  favorable  condition  of  temperature  and  food  supply 
the  growth  of  the  plant  is  extremely  rapid.     When  the  yeast- 
plant  forms  spores,  which  it  does  not  do  very  abundantly  under 
ordinary  conditions  of  growth,  the  contents  of  one  of  the  egg- 
shaped  cells  will  be  seen  to  divide  into  four  portions  each  of 
which  becomes  spherical  in  form  and  secretes  about  itself  a  wall 
of  its  own.     Then,  when  the  wall  of  the  mother-cell  breaks  down, 
the  spores  separate  from  each  other  and  may  be  distinguished 
from   the  ordinary  yeast-cell    by  their  smaller  size,   spherical 
shape  and  thicker  wall.      It  is  on  account  of  their  thicker  wall, 
and  probably,  too,  in  consequence  of  some  difference  in  the 
structure  of  the  living  substance  within  that  they  are  able  to  re- 
sist the  harmful  influence  of  extreme  temperatures  much  better 
than  the  ordinary  yeast-cell.      If    the  conditions  favorable  to 
rapid  growth  become  for  any  reason  unfavorable,  the  yeast  plant 
is  likely  to  undertake  the  formation  of  spores. 

The  particular  substance  that  yeast  attacks  is  cane-sugar. 
This  it  splits  up,  during  its  life-processes,  into  carbonic-acid-gas 
and  alcohol.  Such  a  process  is  called  fermentation,  or  more  pre- 
cisely, alcoholic  fermentation,  because  there  are  various  kinds 
of  fermentation  which  go  on  under  different  circumstances 


74 


Minnesota  Plant  Life. 


through  the  activity  of  different  organisms.  The  peculiarity  of 
the  yeast  plant  is  its  capacity  for  setting  up  alcoholic  fermenta- 
tion and  no  other  kind. 

Besides  the  common  yeasts  a  number  of  others  exist.  One 
kind  which  grows  in  cabbage,  after  it  is  cooked,  produces  the 
substances  which  give  the  flavor  of  sauerkraut.  Another  kind 
when  introduced  into  milk  causes  it  to  ferment,  and  in  the  re- 
gion of  the  Caucasus  is  used  by  the  Tartars  to  change  goat's  or 
camel's  milk  into  an  intoxicating  liquor. 

Plum-pockets.  Very 
closely  related  to  the  yeasts 
is  a  group  of  parasitic  fungi 
capable  of  attacking  a  va- 
riety of  plant-tissues.  One 
kind,  when  it  infects  the 
young  fruits  of  the  plum  or 
cherry  produces  what  is 
known  as  plum-pocket. 
When  such  a  fungus  grows 
upon  a  plum  it  distorts  it 
and  gives  it  a  singular,  ir- 
regular baggy  appearance 
which  is  easily  recognized. 
The  poplar  trees  in  Minne- 
sota are  very  often  attacked 
by  a  pocket-fungus,  which 
changes  their  green  pods 
into  yellow  sacs  distinctly 
larger  than  the  ordinary 
pod.  On  cherry  trees,  a 
witch's  broom  formation  in 
which  the  growth  of  the 
twigs  is  disordered,  results  from  the  presence  of  a  fungus  of  this 
group,  and  upon  alders  another  witch's  broom  arises  under  sim- 
ilar conditions. 

Morels.  In  the  sac-fungi  which  have  been  described  no 
conspicuous  special  body  is  developed ;  but  in  the  higher  forms 
large  bodies,  rivalling  the  mushrooms  in  size,  and  of  a  great 
variety  of  form  and  structure  may  be  produced.  Of  such,  one 


FIG.  25.     Pocket-fungus  on  sand-cherry.     After 
Bailey.     Bull.  70,  Cornell  Ag.  Kxp.  Station. 


Minnesota  Plant  Life. 


75 


of  the  best  known  is  the  morel.     This  superficially  resembles, 
to  some  degree,  the  stinkhorn.      It  grows  upon  the  ground 
and  the  fruit-body  consists  of  a  hollow,  cylindrical  stem,  some- 
times three  or  four  inches  in 
height  and  an  inch  in  diameter. 
The  texture,  however,  is  much 
firmer  than  that  of  the  stink- 
horn stem  and  the  cap  upon 
the  end,  though  wrinkled  like 
the  stinkhorn  cap,  is  continu- 
ous   with    the   stem    and   not 
slimy  nor  vile-smelling.     Mo- 
rels are  edible  and  are  said  to 
be  especially  prized  in  Bohe- 
mia.     They   are   often   found 
growing  in  Minnesota  woods 
and  upon  Minnesota  hillsides, 
where  their  fruit-bodies,  unlike 
those  of  the  stinkhorn,  ripen  in 
the  spring.     If  one  should  ex- 
amine under  a  microscope  a 
thin  section  cut  through  the 
wrinkled  surface  of  the  cap,  it 
would  be  perceived  that  it  con- 
sists almost  entirely  of  sacs,  in 
each  of  which  eight  oval  spores 
are  produced  in  a  row.     Each 
sac  is  cylindrical  in  form  and 
not  much  larger  in   diameter 
than  the  spores  which  fill  it. 
When  ripe  the  ends  of  the  sacs 
break    or    dissolve    and    the 
spores  pour  out  one  after  an- 
other, but  they  are  not,  as  was 
the  case  in  the  stinkhorn,  uni- 
versally carried  away  by  insects,  for  they  depend  rather  upon  the 
wind  and  the  rains  for  their  distribution. 

A  number  of  plants  closely  related- to  the  morel  may  be  dis- 
tinguished by  the  different  shapes  of  their  caps.    In  one  the  cap 


FIG.  26.     A  morel  fruit- body. 
After  I^loyd. 


76  Minnesota  Plant  Life, 

is  saddle-shaped ;  in  another  somewhat  urn-shaped ;  in  a  third 
the  whole  fruit-body  is  club-shaped  and  closely  resembles  some 
forms  of  the  club-fungi  which  have  been  described  above.  In 
some  the  cap  is  peculiarly  coiled  and  twisted,  looking  like  a 
knot  of  angleworms.  The  colors  of  these  plants  are  various — 
white,  brown,  slate-colored,  yellowish,  pinkish  or  red.  They 
occur  sometimes  upon  much  decayed  logs,  but  the  majority  of 
them  are  terrestrial.  A  few  are  of  an  almost  gelatinous  con- 
sistency but  a  greater  number  have,  to  the  touch,  rather  the  feel- 
ing of  cartilage.  Several  of  them  besides  the  morel  are  edible 


FIG.  27.     Cup-fungi  growing  on  decaying  twig.     After  I^loyd. 

and  I  do  not  know  of  any  that  are  violently  poisonous,  although 
from  their  texture,  a  number  of  them  would  scarcely  be  attrac- 
tive. 

Cup-fungi.  Not  a  distant  relative  of  the  morel  is  the  cup- 
fungus,  which  in  its  numerous  varieties  is  doubtless  familiar  to 
many  of  the  readers  of  this  volume.  A  dark  slate-colored  spe- 
cies of  cup-fungus  is  abundant  in  Minnesota  woods  in  early 
spring  and  produces  cups  an  inch  or  more  in  diameter.  If  one 
cuts  such  a  cup  in  two  and  looks  at  the  cut  surface  it  will  be 
found  that  the  whole  fruit-body  has  a  distinct  lining  like  a  por- 


Minnesota  Plant  Life.  77 

celain  kettle.  The  lining-layer  is  made  up  entirely  of  sacs  and 
accessory  threads  running  parallel  with  them.  All  of  the  sacs 
are  cylindrical,  slender  and  arranged  perpendicular  to  the  inner 
surface  of  the  cup,  while  in  each  sac  there  are  eight  spores,  ovoid 
in  shape  and  developed  in  a  row  just  as  in  the  morel. 

Another  kind  of  cup-fungus  is  scarlet,  almost  as  large  as  the 
one  just  described  and  equally  familiar  to  most  persons  who  go 
into  the  woods  with  open  eyes.  Besides  such  large  cup-fungi 
there  are  a  great  number  of  smaller  kinds,  some  of  them  grad- 
ing down  to  the  size  of  a  pin-point,  while  between  these  and  the 
large  ones  are  all  sorts  of  intermediate  sizes.  They  differ  too 
in  color  and  in  form  and  many  of  them  are  saucer-shaped,  or 
merely  flat  discs,  circular  in  outline.  Such  small  discs  of  a 
bright  yellow,  or  bright  red  color,  are  abundantly  produced 
upon  decaying  wood  and  leaves. 

In  distinguishing  the  different  kinds  of  cup-fungi  the  char- 
acter of  the  margin  should  be  observed.  This  is  sometimes 
furnished  with  bristles  or  scales ;  sometimes  it  is  smooth ;  some- 
times it  is  rolled  back,  or  it  may  be  rolled  in  over  the  centre  of 
the  cup,  disc  or  saucer.  It  is  not  possible,  however,  to  recog- 
nize exactly  all  the  different  cup-fungi  without  an  examination 
of  their  spores,  for  special  sorts  develop  special  kinds  of  spores 
in  their  sacs.  Sometimes  the  spores  are  without  partitions, 
while  in  other  instances  they  are  divided  into  little  chambers. 
They  may  be  smooth  or  provided  with  knobs,  spines  or  emer- 
gences. Growing  in  the  same  layer  with  the  sacs  are  com- 
monly to  be  found  much  slenderer  threads,  which  help  to  keep 
the  sacs  moist  while  they  are  developing  their  rows  of  spores. 
When  the  cup-fungus  has  matured  its  spores,  the  ends  of  the 
sacs — which  all  lie  at  the  same  level  in  the  surface  of  the  cup- 
lining — open  or  dissolve,  and  the  spores  are  then  thrown  out. 

One  kind  of  cup-fungus  which  is  common  on  manure-piles 
has  a  special  explosive  method  of  ejecting  its  spores.  If  such  a 
cup  is  taken  between  the  finger  and  thumb,  held  to  the  light  and 
pressed  gently,  the  sacs  all  open  at  once  and  violently  eject  their 
spores,  so  that  for  an  instant  a  little  wreath  of  smoke  seems  to 
fly  from  the  top  of  the  cup.  This  phenomenon  is  caused  by  a 
cloud  of  several  thousand  spores  escaping  simultaneously.  The 
spores  in  certain  species  are  net  individually  shot  out  from  the 


78  Minnesota  Plant  Life. 

surface  of  the  cup,  but  rather  the  sacs  themselves  with  the  spores 
enclosed. 

A  particular  variety  of  cup-fungus,  very  abundant  in  the 
woods  of  Minnesota,  grows  upon  the  ground  and  produces  a 
hard,  black  underground  tuber,  as  large  as  the  end  of  one's 
thumb.  This  tuber  has  a  firm  skin,  but  when  it  is  cut  open  the 
interior  is  softer  and  white.  A  bud  forming  under  the  skin  of  such 
a  tuber  develops  a  fruit-body,  cup-like  in  shape,  and  provided 
with  a  slender  stalk.  A  relative  of  this  fungus  produces  on  the 
twigs  of  tamaracks  nut-like  swellings  from  which  little  cups 
arise. 

Maple-leaf  tar  spots.  A  great  variety  of  cup-fungi  and  disc- 
fungi  are  parasitic  upon  the  leaves  of  growing  plants.  Possibly 
the  most  conspicuous  one  in  Minnesota  is  the  tar-spot  fungus 
of  the  maple,  often  seen  developed  on  the  upper  surfaces  of 
maple  leaves  as  one  or  more  black  shiny  bodies,  a  quarter  of 
an  inch  or  so  in  diameter,  and  of  an  irregular  roundish  shape. 
These  are  the  fruit-bodies  of  the  tar-spot  fungus,  and  while  the 
vegetative  portion  of  the  fungus  is  growing  within  the  tissues 
of  the  leaf,  the  reproductive  portion,  consisting  of  a  layer  of 
sacs  with  spores  enclosed,  destroys  the  epidermis  of  the  leaf  and 
produces  the  conspicuous  spot. 

Truffles.  The  fruit-bodies  of  a  few  sac-fungi  are  developed 
underground  and  here  belong  the  truffles,  which  may  be  de- 
scribed in  a  general  way  as  underground  cup-fungi,  in  which 
the  cups  have  closed  up  into  irregular  egg-shaped  bodies.  Upon 
the  rotting  of  the  truffle  the  labyrinthine  sac-layers  are  exposed 
and  the  spores  escape.  Truffles  are  among  the  most  esteemed 
delicacies  of  the  gourmet. 

Green  and  blue  moulds.  Curiously  enough  the  green  and 
blue  moulds  which  occur  on  bread,  leather,  decaying  fruits  and 
other  objects  of  that  sort  are  rather  close  relatives  of  the  truffles. 
As  was  observed  during  the  description  of  the  rust-fungi,  a 
fungus  often  has  the  power  of  producing  more  than  one  kind 
of  fruit-body.  The  blue  mould — if  for  a  sufficient  time  left  to 
itself — will  form  in  addition  to  the  ordinary  patches  of  blue 
spores  arranged  in  chains  on  swollen  terminal  cells  of  some  of 
its  threads,  also  certain  miniature  yellow  truffles,  not  much 
larger  than  a  pin-point.  These  little  truffle-like  fruits,  just  as 


Minnesota  Plant  Life, 


79 


happened  in  the  study  of  the  rust-fungi,  were  supposed  orig- 
inally, by  botanists,  to  characterize  entirely  independent  plants, 
but  it  is  now  known  that  the  blue  moulds  and  their  relatives 
the  green  moulds  can,  under  suitable  conditions  of  growth  and 
nutriment,  produce  the  sac-fruit-bodies.  Thus  it  is  apparent 
that  in  the  ability  to  form  such  tiny  orange-colored  "truffles" 
they  are  quite  unlike  the  black  mould  which  had  no  such  ca- 
pacity. The  general  plant-bodies  of  the  different  sorts  of 
moulds  and  their  general  life-habits  are,  however,  very  similar, 
so  that  popularly  they  are  all  included  under  the  same  name. 
Botanically,  black  moulds  and  blue  moulds  are  quite  distinct. 


Chapter  XI. 

Blights,  Black  Fungi  and  Root-fungi* 


Blights.  There  remains  to  be  considered  a  large  group  of 
sac-fungi,  which  from  the  color  of  their  fruit-bodies  are  classed 
together  under  the  name  of  black  fungi.  Very  good  examples 
of  the  black  fungi  are  furnished  by  the  blights  which  occur  on 
the  leaves  of  the  higher  plants.  As  a  type,  may  be  selected  the 
lilac-blight,  which  in  autumn  forms  a  white  scurf  on  lilac  leaves. 
This  scurf  is  the  vegetative  body  of  the  blight  and  consists  of 
a  cobwebby  mass  of  delicate,  white,  branching  filaments,  some 
of  which  penetrate  the  tissues  of  the  leaf,  while  others  spread 
themselves  over  its  surface.  If  one,  in  the  autumn,  looks  closely 
at  a  blighted  lilac  leaf  it  will  be  discovered  that  there  are  pres- 
ent on  its  surface  a  great  number  of  tiny  black  specks  which  by 
the  naked  eye  can  be  seen  to  have  a  spherical  shape.  These  are 
the  fruit-bodies  of  the  blight.  Within  the  black  skin  of  each, 
sacs  are  formed,  much  as  in  the  truffle,  and  in  the  sacs  spores 
are  produced.  The  fruits  of  the  blights  are  many  of  them  re- 
markable for  their  development  of  peculiar  anchor-like  append- 
ages which  grow  out  from  the  surface.  In  the  lilac-blight 
these  appendages  are  branched  in  a  regular  fashion  forming  at 
the  ends  a  series  of  curved  prongs.  The  willow-blight,  on  wil- 
low leaves,  has  the  ends  of  its  fruit-appendages  hooked  and  such 
blights  are  called  hooked  blights.  The  blights  common  on 
grass  leaves  in  autumn  and  causing  portions  of  the  turf  to  look 
as  if  a  little  whitewash  had  been  spilled  upon  it  are  supplied 
with  fruit-appendages  which  are  not  hooked  or  branched  at  the 
end.  In  another  sort  of  blight  the  appendages  are  sharply 
pointed  like  thorns. 

Toadstool-blight.  A  few  of  the  so-called  black  fungi  belie 
their  name,  for  instead  of  black,  their  color  is  rather  yellowish 


Minnesota  Plant  Life.  81 

% 

or  red.  Here  may  be  included  a  curious  fungus  which  is  par- 
asitic on  toadstools.  When  a  toadstool  is  affected  by  this  par- 
asite the  gills  are  all  destroyed  and  the  area  they  occupied  pre- 
sents a  pimply  red  surface.  The  pimples  are  small,  about  the 
size  of  a  pin-head,  and  in  each  of  them  is  developed  a  mass  of 
spore-sacs.  Such  a  plant  illustrates  the  tendency  of  what  were 
independent  fruit-bodies  in  the  truffles,  the  blights  and  the  blue 
moulds,  to  aggregate  themselves  into  layers.  Such  layers  are 
in  higher  forms  of  black  fungi  variously  disposed  over  branch- 
ing or  swollen  bases,  so  that  a  large  compound  fruit-body  is 
developed. 

Ergots.  A  good  example  of  an  interesting  black  fungus 
with  a  compound  fruit-body  is  the  well-known  ergot  of  rye. 
Ergots  occur,  however,  upon  other  plants  than  the  rye,  and, 
for  instance,  a  very  interesting  kind  is  found  in  the  fruiting 
panicles  of  the  wild  rice.  The  life-history  of  an  ergot  is  about 
as  follows :  The  plant-body  develops  within  the  tissues  of  the 
grass  and  when  the  grass  is  ready  to  set  its  fruits,  the  ergot 
plant,  somewhat  after  the  manner  of  smuts,  produces  in  some 
of  the  .kernels,  a  dense  network  of  filaments,  occupying  the 
place  of  the  grain.  The  ergot  does  not  here,  however,  form  its 
spores  as  the  smuts  do,  but  gives  rise  rather  to  a  tuberous 
propagative  body,  consisting  of  a  softer  white  interior,  with  a 
black  shell  and  exactly  comparable  to  the  underground  tubers 
formed,  as  mentioned  above,  by  one  kind  of  cup-fungus.  Such 
ergot  tubers  take  about  the  same  shape  as  the  rye  kernel,  finally 
falling  out  from  between  the  chaffy  scales  of  the  rye  and  lying 
dormant  over  winter.  In  the  spring,  buds  arise  under  the  skin 
of  the  tuber  and  grow  out  into  little  slender  threads  and  at  the 
end  of  each  a  more  or  less  spherical  swelling  appears.  The  sur- 
face of  the  swelling  is  occupied  by  a  layer  of  ergot  fruit-bodies, 
in  each  of  which  a  group  of  slender  sacs,  with  long  jointed 
spores,  is  developed.  It  should  be  added  that  other  sorts  of 
spores,  ovoid  in  form,  are  produced  upon  wrinkles  at  the  surface 
of  the  propagative  tuber,  so  that  as  in  so  many  other  fungi, 
there  are  here  two  kinds  of  spore-cells.  Either  variety  of  spore 
falling  upon  the  proper  host  plant  will  infect  it  and  initiate  the 
development  of  a  new  ergot  plant-body. 

7 


82 


Minnesota  Plant  Life. 


Ergot  is  of  considerable  commercial  importance  on  account 
of  its  tubers,  which  form  certain  alkaloids  used  in  medicine. 
Of  fungus  alkaloids  there  is  a  considerable  group,  of  which 
those  in  poisonous  mushrooms,  poisonous  pore-fungi  and  er- 
got-tubers are  examples.  Ergot  in  rye  sometimes  occurs  in 
sufficient  quantities  to  poison  persons  or  animals  that  eat  the 
grain  and  where  rye-bread  is  a  staple  article  of  diet  it  is  neces- 
sary to  remove  the  ergot-tubers  before  the  rye  is  ground  into 
flour. 

Caterpillar  fungi. 
Very  closely  related 
to  the  ergot  is  a  small 
group  of  fungi  which 
live  parasitically  in 
caterpillars  and  other 
insect  larvae.  Some- 
times on  mossy  banks 
one  will  notice  a  little 
reddish-yellow,  pimply, 
club-shaped  body  ris- 
ing up  among  the 
mosses  and  an  inch  or 
more  in  height.  If 
this  is  carefully  pulled 
out  from  between  the 
moss-plants  it  will  be 
found  to  spring  from 
the  body  of  some  dead 
caterpillar  or  other  in- 
sect. The  plant-body 
of  the  caterpillar-fun- 
gus grows  within  the 

tissues  of  the  insect  and  forms  there  a  tuber-body  similar  to 
that  of  the  ergot.  From  this  a  bud  develops  into  the  club- 
shaped  stem  over  the  end  of  which,  and  covering  the  sides, 
a  layer  of  somewhat  bottle-shaped  fruit-bodies  is  produced. 
One  kind  of  caterpillar-fungus  has  its  compound  fruit-body 
branched,  so  that  the  unfortunate  caterpillar  seems  to  be  carry- 


FlG. 


I,eaf-spot  disease  caused  by  fungus. 
After  Halsted. 


Minnesota  Plant  Life.  83 

ing  upon  its  head  an  elkhorn-like  protuberance  three  or  four 
inches  long.  A  remarkable  variety  of  caterpillar-fungus  has  a 
slender  tongue  of  sterile  tissue  projected  beyond  the  end  of  the 
fruit-body  area. 

Leaf-spot-fungi.  Among  the  black  fungi  a  considerable 
number  form  what  are  known  as  leaf-spots.  Very  often  on 
leaves  little  pale  areas  develop,  not  infrequently  surrounded  by 
a  reddish  circle.  This  red  circle  is  caused  by  a  secretion  of  red 
coloring  matter  by  the  leaf,  owing  to  the  irritation  occasioned 


FIG.  29.     I^eaf-spot  fungus  growing  on  pear  leaves.     After  Duggar.     Bull.  145,  Cornell  Ag. 

Kxpt.  Station. 

by  the  spot  fungus.  The  pale  centre  of  the  red  circle  is  the  in- 
jured portion  of  the  leaf,  where  the  fungus  has  destroyed  the 
cells  and  devoured  the  particles  of  leaf-green.  If  in  autumn  one 
looks  very  closely  at  a  leaf-spot  he  will  generally  be  able  to  see 
the  tiny  black  fruit-bodies  of  the  fungus.  Usually  they  are 
separate  from  each  other  as  in  the  blight,  but  a  considerable 
proportion  of  them  are  blended  together  in  layers,  as  was  de- 
scribed for  the  much  larger  fungus,  parasitic  on  the  toadstool. 


84  Minnesota  Plant  Life. 

There  must  be  at  least  a  thousand  different  kinds  of  leaf-spot 
fungi  growing  in  Minnesota.  Not  all  leaf-spot  fungi  are  cer- 
tainly black  fungi;  but  the  great  majority  of  them  belong  to 
that  group.  Neither  do  all  leaf-spot  fungi  develop  fruit-bodies, 
for  some  of  them  are  able  to  form  only  a  simpler  sort  of  spore- 
cluster.  Yet  in  most  instances  it  is  believed  that  this  is  because 
the  fungus  has  abandoned  for  some  reason  the  formation  of 
true  fruit-bodies.  As  already  observed  in  the  account  of  the 
wheat  rust — a  most  instructive  object  of  study — a  fungus  may 
acquire  the  habit  of  developing  one  kind  of  fruit-body  upon 
one  leaf  and  another  kind  upon  another.  It  is  very  probable, 


FIG.  30.    Fungus  spot-disease  of  strawberry  leaf.     After  Bailey.     Bull.  79,  Cornell  Univ.  Ag. 

Expt.  Station. 

v/here  leaf-spot  fungi  fail  to  develop  their  ordinary  fruit-bod- 
ies and  provide  themselves  with  spore  clusters,  that  they 
may  on  other  plants  develop  the  true  fruit-bodies,  or  that 
they  have,  as  is  often  probable,  ceased  altogether  to  produce 
them. 

Not  only  do  these  spot-fungi  find  pasture  upon  the  tissues 
of  living  leaves  but  closely  related  forms  browse  upon  old  pieces 
of  paper,  upon  straw,  leather,  decaying  cloth,  the  shells  of  nuts 
and  seeds,  and  even  upon  such  curious  fields  as  the  inner  sur- 
face of  roasted  chestnuts,  the  feathers  of  fowls,  the  hair  and 
hoofs  of  cattle,  and,  in  short,  wherever  they  can  find  food-ma- 
terials suitable  for  their  growth. 


Minnesota  Plant  Life. 


Twig-fungi.      A  large  group  of  black  fungi  grow  upon  twigs 
and  these  may  be  known  generally  as  twig-fungi.     One  of  the 
most  prominent  forms  is  the  black  knot  of  plum  and  cherry 
twigs,  a  plant  which  is  very  common  upon  various  species  of 
wild   plums   in   Minnesota,   and   upon   the   wild   choke-cherry. 
It    forms  black  swollen  bodies,  half   an  inch  or  so  in  height! 
and  two  or  three  inches  or  more 
in    length,    distorting    the    twig 
where  it  grows,  and  bursting  the 
bark  to  display  its  layers  of  black 
fruit-bodies.     A    close   examina- 
tion  of  a  black   knot   mass  will 
show  that  its  surface  is  covered 
with  little  round  emergences  or 
pustules,    and    each    emergence 
marks  the  point  where  a  bottle- 
shaped  fruit-body  is  imbedded  in 
the  general  layer.     As  before  no- 
ticed, each  fruit-body  contains  its 
lining  of  sacs  in  which  the  black 
knot  spores  are  found — for  the 
elaboration  of  which  the  plant- 
body    derives    sufficient    s  u  s  t  e- 
nance  from  the  cells  of  the  twig 
which   it   robs   of  its  sap.      The 
black  knot  is  but  a  single  exam- 
ple of    a  large   group   of    black 
twig-fungi.     Some  of  them  like 
the  black  coin-fungus  form  coin- 
shaped  discs.     Others  develop  a 
few     little     gourd-shaped     fruit- 
bodies  in  a  group.     One  curious  kind  of  which  there  are  in 
different  parts  of  the  world  about  400  species  known,  forms  on 
twigs  little  black  patches  in  which  three  or  four  fruit-bodies  are 
imbedded,  one  of  the  group  being  entirely  different  from  the 
rest.     The  central   one,   in  its  bottle-shaped  cavity,   produces 
spores  displayed  on  stalks,  while  the  others  produce  spores  de- 
veloped   in   sacs.      The  spores  produced   on   stalks  are  much 


FIG.  31.  Fungus  spot-disease  on  leaf  of 
false  Solomon's  seal.  After  Hal- 
sted. 


86 


Minnesota  Plant  Life. 


smaller  than  the  others.  An  explanation  of  this  peculiarity  may 
be  obtained  from  the  behavior  of  the  blue  mould.  It  will  be 
remembered  that  in  the  latter  kind  of  mould,  spores  were  ordi- 
narily formed  on  branches  loosely  distributed  over  the  plant, 
while  at  other  times  tiny  orange  truffle-like  fruit-bodies  arose 
after  the  method  of  sac-fungi.  Now  if  it  can  be  imagined  that 
the  loosely  formed  spores  of  the  blue  mould  are  aggregated  to- 
gether in  a  bottle-shaped  structure,  they  lining  the  interior  of 
the  bottle,  there  would  arise  a  fruit-body  like  the  peculiar  cen- 
tral one  of  the 
plant  in  question. 
The  name  of  a 
plant,  which 
forms  these  two 
kinds  of  fruit- 
bodies  is  Falsa. 
Plants  somewhat 
related  to  the  Val- 
sas  are  found  on 
butternut  twigs 
where  they  form 
little  low  black 
mounds. 

Staghorn-fungi. 
The  last  black 
fungus  that  needs 
consideration  in 
this  general 
survey  of  the  im- 
portant types  is 
sometimes  called 

the  staghorn-fungus.  It  grows  upon  stumps,  decaying  timbers, 
sometimes  on  rafters  in  cellars,  or  in  damp  places  about  barns 
or  granaries,  and  is  a  very  curious  looking  object  indeed.  It 
is  often  three  or  four  inches  in  height  and  shaped  much  like  one 
of  the  antlers  of  a  moose.  Its  whole  surface  is  warty  and  black, 
each  pustule  marking  the  position  of  a  fruit-body  The  interior 
of  the  plant  is  white  and  consists  of  a  very  densely  tangled  skein 
of  threads.  A  smaller  species  is  unbranched  but  stands  up  like 


FIG.  32.     Fungus  spot-disease  on  pear.    After  Duggar.     Bull. 
145,  Cornell  Ag.  E)xpt.  Station. 


Minnesota  Plant 


a  little  black  Indian  club  an  inch  or  more  in  height  and  a  quar- 
ter to  half  an  inch  thick  through  the  thickest  part. 

The  life  of  a  fungus.  There  have  now  been  passed  in  re- 
view a  sufficient  number  of  fungi  to  give  a  fair  idea  of  the  group 
as  a  whole.  But  the  great  variety  of  different  species,  and  the 
almost  innumerable  peculiarities  of  structure,  form  and  function 
which  are  possible,  can  scarcely  be  comprehended  by  any  but  a 
careful  student  of  the  group. 
Some  general  observations 
concerning  their  lives  de- 
serve to  be  made. 

Regarding  their  nutrition 
this  may  be  said — that  they 
are  animal-like.  Not  one  of 
them  has  the  power  of  mak- 
ing starch  out  of  gas  and 
water,  as  green  plants  have, 
and  all  of  them  must  obtain 
organic  substances  from 
which  to  construct  their 
bodies.  In  a  great  majority 
the  vegetative  area  is  incon- 
spicuous because  it  is  con- 
cealed in  the  sub-stratum 
upon  which  the  fungus  lives. 
The  sub-stratum  may  be  the 
soil,  a  rotting  log,  a  living 
twig  or  leaf,  a  piece  of  pa- 
per, the  hair  or  feathers  of 
an  animal  or  bird,  a  bit  of 
dung,  or,  for  aquatic  fungi, 
various  similar  objects  submerged  in  lakes,  streams,  pools  or 
springs.  Concerning  the  reproduction  of  the  fungi,  it  may  be 
noted  that  the  higher  forms  commonly  develop  at  least  two 
kinds  of  spores,  one  being  entirely  disconnected  with  the  breed- 
ing-habits of  the  plant,  the  other  dependent  upon  the  breeding 
act — a  process  which  often  takes  place  upon  areas  concealed  in 
the  sub-stratum.  The  rudiments  of  all  true  fruit-bodies,  such 
as  those  of  the  cup-fungus,  the  morel,  the  ergot,  the  cater- 


FlG. 


Fungus  spot-disease  of  bean  pods. 
After  Halsted. 


88 


Minnesota  Plant  Life. 


pillar  fungus,  the  black  knot  and  all  the  other  sac-fungi,  arise 
as  a  necessary  consequence  of  some  fusion  of  cells,  equivalent 
to  that  which  took  place  in  the  black  moulds.  In  the  stalk- 
fungi,  to  which  group  the  mushrooms,  puff-balls,  club-fungi  and 
all  their  relatives  belong,  it  is  not  so  certain  that  a  breeding-act 
is  always  the  necessary  precursor  of  the  fruit-body,  but  there  is 
much  good  evidence  in 
favor  of  such  a  supposi- 
tion. 

All  of  the  fungi  which 
have  been  considered  up 
to  this  point  may  be  re- 
garded as  derived  from 
certain  of  the  lower  algse, 
while  the  bacteria — yet 
to  be  discussed — are  very 
closely  related  to  the 
blue-green  algae.  The  al- 
gal fungi  seem,  for  the 
most  part,  to  be  connect- 
ed with  the  pond-scums, 
leading  over  to  such 
forms  as  the  black  mould, 
or  with  the  green  felts, 
leading  over  to  mildews 
and  fish-moulds.  It  is 
reasonable  to  suppose 
that  all  of  the  higher 
fungi  which  have  thus  far 
been  passed  in  review  are 
derived,  by  a  continuous 
series  of  improvements, 
from  the  algal  fungi. 

Root-fungi.  There  are  a  few  rather  remarkable  types  of 
fungi  which  should  be  treated  separately.  One  of  these  is  not 
commonly  known  to  make  fruits  of  any  sort,  and,  since  botan- 
ists depend  upon  fruit-bodies  as  the  basis  of  their  classification, 
it  is  difficult  to  say  where  these  fungi  about  to  be  considered 
should  be  placed  in  the  general  system.  They  will  be  found 


FIG.  34.     Twig-fungus    on    currant    canes.      After 
Durand.     Bull.  125,  Cornell  Expt.  Station. 


Minnesota  Plant  Life. 


89 


encircling  the  roots  of  many  kinds  of  trees  or  herbs,  and  some- 
times developing  within  the  outer  tissues  of  roots  or  under- 
ground stems  belonging  to  plants  growing  in  very  rich  soil. 
An  example  of  the  first  kind  is  to  be  met  with  on  rootlets  of  the 
tamarack.  Another  is  found  upon  the  rootlets  of  the  oak,  and, 
often,  too,  upon  the  young  roots  of  birches.  Such  fungi  form 
rather  thin,  felted  masses  inclosing  the  roots  as  in  sheaths.  The 
sheaths  become  of  a  dark  brown  color  as  they  grow  older,  but 
at  first  they  are  almost  white.  So  constant  is  the  association 
of  the  fungi  with  the  roots  or  subterranean  stems  of  some  plants 
that  they  may  be  regarded  as  necessary  concomitants  of  these 
higher  plants.  It  is  probable  that  they  play  a  very  important 
part  in  the  nourishment  of  roots  which  they  inclose  or  infest. 
It  would  seem  that  they  have  something  to  do  with  the  conver- 
sion of  the  food  materials  in  the  soil  into  a  condition  in  which 
they  are  the  more  easily  absorbed  and  assimilated  by  the  roots 
themselves.  If  this  suggestion,  which  is  generally  accepted 
among  botanists,  is  the  correct  one,  there  is  presented  the  inter- 
esting fact  that  all  the  tamarack  trees  in  a  swamp  and  all  the  oak 
trees  by  the  road-side  are  largely  dependent  for  their  life  and 
prosperity  upon  the  little  sheaths  of  fungi  which  feed  their  roots. 
In  a  considerable  number  of  plants  the  fungal  threads  do  not 
form  a  sheath  around  the  outside  of  the  root  but  grow  in  mi- 
croscopic tangled  masses  resembling  skeins  of  yarn,  one  mass 
in  each  of  certain  outside  cells  of  the  root.  The  orchids  of  Min- 
nesota are  provided  with  such  structures  in  their  roots  and  the 
Dutchman's  pipe,  the  Pyrolas,  and  a  number  of  other  plants 
which  live  in  humus  soil,  resemble  the  orchids  in  this  respect. 
Sometimes  underground  stems  among  the  orchids  are,  through 
the  irritation  of  the  fungus  in  their  outside  cells,  peculiarly  knot- 
ted and  distorted  into  structures  quite  different  from  the  ordi- 
nary forms  of  growth.  A  very  good  example  of  this  is  the 
coral-root  orchid.  Really  this  variety  of  orchid  has  no  roots  at 
all  and  the  underground  portion  is  a  curiously  modified  branch- 
ing root-stock,  which  from  its  resemblance  to  coral,  gives  occa- 
sion for  the  common  name  of  the  plant.  There  is  good  reason  to 
suppose  that  some  of  such  underground  fungus-masses  which 
enclose  the  roots  of  trees,  or  develop  themselves  in  the  roots  of 
humus  plants,  were  originally  the  vegetative  bodies  of  truffle- 


90  Minnesota  Plant  Life. 

like  plants,  and  that  on  account  of  long  association  with  the 
roots  they  have  abandoned  their  fruiting  habits.  Seemingly 
they  are  able  to  maintain  themselves  without  going  to  the 
trouble  of  fruiting,  and  in  a  sense  they  may  be  regarded  as  form- 
ing a  partnership  with  the  higher  plants  to  which  they  have  at- 
tached themselves.  They  can  scarcely  be  called  parasites  be- 
cause their  presence  is  not  harmful  to  the  higher  plant,  but, 
rather,  as  has  been  explained,  beneficial,  because  they  enable  it 
to  use  substances  in  its  nutrition  which  would  otherwise  be  be- 
yond its  power  to  absorb  from  the  soil.  Among  the  bacteria 
there  are  similar  partnerships  with  higher  plants,  and  they  will 
be  considered  in  their  place. 

Ear-fungi.  There  are  some  other  obscure  forms  of  fungi, 
such  as  the  curious  little  necklace-like  bodies,  which  sometimes 
live  in  the  ears  and  throats  of  birds  and  animals.  They  may 
be  considered  as  truly  parasitic,  but  it  is  not  easy  to  say  exactly 
where  they  belong  in  an  orderly  classification.  Sometimes  they 
attack  men  and  women  and  the  bad  habit  of  dropping  sweet-oil 
in  the  ear  as  a  remedy  for  ear-ache  may  stimulate  their  growth. 


Chapter  XII. 
Lichens  and  Beetle-fungi. 


The  life  of  a  lichen.  The  group  of  plants  known  as  lichens 
is  familiar  to  all  observers.  Some  varieties  are  called  gray  or 
hanging  moss  by  persons  who  do  not  discriminate  accurately 
between  these  plants  and  the  very  different  forms  which  are 
rightly  known  as  mosses.  A  still  greater  error  is  made  in  com- 
mon speech,  when  the  little  hanging,  gray,  flowering  plant,  so 
abundant  in  the  south  upon  tree-branches,  is  given  the  name  of 
''Spanish  moss."  Lichens  are  found  in  a  great  variety  of  posi- 
tions. They  are  exceedingly  prevalent  all  over  the  world  on 
rocks,  making  characteristic  patches  on  weathered  cliffs,  walls, 
boulders,  and  pebbles,  provided  there  be  not  some  constant  agi- 
tation upon  the  surface  of  the  rock,  as  by  drifting  sand  or  surf, 
which  might  prevent  their  growth.  They  are  seen  very  com- 
monly upon  the  trunks  of  trees,  usually  preferring  the  side 
toward  the  north.  One  characteristic  lichen  hangs  from  the 
branches  of  tamaracks  everywhere  in  Minnesota,  and  is  some- 
times called  "old  man's  beard"  from  its  gray  color  and  thread- 
like texture.  Other  varieties  produce  little  patches  on  tree 
trunks  and  they  may  be  distinguished  by  their  generally  circular 
form,  by  their  flat  habit  of  growth,  and  by  their  greenish,  red, 
yellow  or  gray  color,  which  is  very  rarely  a  pure  leaf  green,  but 
varies  more  or  less  toward  the  other  shades. 

Stone-corroding  lichens.  Lichens  upon  stones  are  very 
often  so  firmly  attached  that  they  cannot  be  removed,  having 
eaten  their  way  into  the  stone  by  means  of  acids  which  they 
secrete  for  that  purpose.  Curiously  enough,  a  lichen  which  can 
live  upon  limestone  is  not  always  able  to  live  upon  sandstone, 
because  it  takes  a  different  kind  of  acid  to  corrode  limestone 
from  that  which  eats  away  the  quartz  of  a  granitic  rock.  A 
great  many  of  the  lichens  upon  stones  are  not,  however,  firmly 


92 


Minnesota  Plant  Life. 


FIG.  35.— Rock-lichens  growing  profusely  in  a  glacial  pot-hole.     Near  Taylor's  Falls.     After 
photograph  by  Mr.  E).  C.  Mills 


Minnesota  Plant  Life. 


93 


attached,  and  such  kinds  may  often,  too,  be  found  upon  tree- 
trunks,  fence-rails,  twigs  or  the  roofs  of  houses.  A  true  rock- 
lichen  does  not  commonly  occur  upon  wood,  so  that  different 
series  of  forms  will  be  found  if  one  examines  the  different  hab- 
itats where  these  plants  are  wont  to  display  themselves. 

Structure  of  lichens.  Lichens  are  very  extraordinary  plants, 
or  rather  pairs  of  plants,  for  a 
lichen  is  essentially  a  partner- 
ship between  a  fungus  and  an 
alga.  Several  different  groups 
of  algae  are  employed  in  the 
building  up  of  lichen  bodies, 
especially  the  blue-green  algae 
—such  as  the  water-flower— 
and  the  bright-green  algae.  I 
do  not  know  of  any  lichens 
which  employ  red  or  brown  al- 
gae in  their  partnership.  Sev- 
eral varieties  of  blue-green  and 
bright-green  algae  are  con- 
cerned, but  a  particular  species 
of  lichen  rarely  exhibits  more 
than  one  kind  of  alga  and  one 
kind  of  fungus  in  its  partner- 
ship-structure. As  will  be  ex- 
plained, such  partnerships  are 
self-perpetuating,  and  the  part- 
nership comes  to  have  the  ap- 
pearance and  very  much  the 
character  of  a  plant-unit,  so 
much  so,  indeed,  that  for  con- 
venience lichens  are  generally 
viewed  as  independent  unit- 
plants  rather  than  as  the 
double  organisms  which  in  reality  they  are. 

If  one  makes  a  very  thin  slice  through  the  plant-body  of  a 
lichen  it  will  be  found  to  consist  of  certain  algal  cells  or  fila- 
ments quite  able  to  propagate  after  their  kind,  and  these  en- 
closed in  a  tangle  of  fungus  filaments  which  are  equally  capable, 


FIG.  36.— "Old  man's  teard."  A  lichen 
growing  attached  to  the  twigs  of  tam- 
arack. I<ake  Superior,  north  shore. 
Natural  size,  six  inches  in  length.  After 
photograph  by  Professor  Bruce  Fink. 


94  Minnesota  Plant  Life. 

for  the  most  part,  of  developing  their  special  types  of  fruit- 
bodies.  In  addition  to  the  algal  propagation  which  goes  on 
among  the  algae  of  the  lichen-body,  and  the  fungal  spore-forma- 
tion which  characterizes  the  fungal  member  of  the  firm,  there 
is  commonly  a  production,  superficially,  of  little  granules,  con- 
sisting of  two  or  three  algal  cells  with  a  web  of  fungal  threads 
around  them.  Such  minute  granules,  which  may,  form  a  green- 
ish dust  over  the  surface  of  the  lichen,  are  separated  from  the 
region  where  they  arise  and  serve  as  special  partnership  propa- 
gative  bodies. 

By  means  of  the  algal  growth  which  goes  on  in  the  lichen 
body,  the  algal  partner  increases  in  size  while  it  is  protected  by 
its  fungus  neighbor.  The  fungus,  too,  grows,  keeping  pace 
with  the  alga,  and  in  this  way  the  double  organism  increases  in 
size.  When  the  fungus  bears  fruits — a  process  which  in  some 
lichen  plant-bodies  occurs  very  seldom,  and  in  a  few  forms  ap- 
parently never — the  spores  that  are  produced  are  in  many  in- 
stances thought  to  be  incapable  of  germination,  and  it  would 
appear  that  then  the  fungal  partner  has  entirely  lost  the  power 
of  existing  independently  of  its  alga.  If  the  algae  are  removed 
by  careful  methods  from  the  plant-body  they  are  usually  able 
to  develop  independently  and  could  not  under  such  circum- 
stances be  distinguished  from  the  same  kinds  of  algae  living 
their  ordinary  life  in  pools  or  moist  places.  There  are,  how- 
ever, exceptions  to  this  rule,  and  some  algae  when  removed 
from  their  long  accustomed  partnership  do  not  find  it  easy  to 
continue  an  independent  existence,  though  in  no  case  are  they 
so  helpless  as  may  be  the  fungi.  It  must  doubtless  be  as- 
sumed that  lichens  began  to  exist  by  the  attachment  of  certain 
fungi  to  algae,  and  that  such  a  relation  proved  mutually  bene- 
ficial. Under  it  the  algae  were  protected  from  desiccation  by  the 
presence  of  the  moist  fungus  threads  and  the  fungi  were  able  to 
absorb  nourishment  from  the  algae,  which  they  in  turn,  by 
means  of  their  leaf-green,  were  able  to  manufacture  from  gas 
and  water.  As  time  went  on  these  partnership  structures  began 
to  improve  along  paths  favorable  to  the  more  perfect  work  of 
the  partnership  as  a  whole,  and  hence  in  lichens  there  have 
arisen  leaf-like  bodies,  and  even  little  tree-like  stems  with  leafy 
expansions  upon  them — not  at  all  an  unreasonable  course  of 


Minnesota  Plant  Life. 


95 


development,  for  clearly  the  problem  of  obtaining  illumination 
is  much  the  same  for  a  lichen-partnership  that  it  is  for  an  inde- 
pendent moss  or  fern. 

Lichen-fungi.  The  kinds  of  fungi  which  have  formed  a  habit 
of  entering  such  lichen-partnerships  are  as  various  as  the  species 
of  algae.  There  are  among  them  a  few  stalk-fungi,  related 
somewhat  to  the  mushroom  group,  and  when  these  fungi  bear 


FIG.  37. — A  lichen  growing  upon  a  rock,  and  covered  with  the  characteristic  saucer-shaped 
fruits  of  its  fungus  component.    After  Atkinson. 

fruit,  in  the  lichen-partnership,  they  produce  their  spores  on 
stalks  in  groups  of  four  just  as  the  mushroom  does.  Most  of 
the  lichen-fungi  are,  however,  sac-fungi,  a  few  of  which  could 
be  classified  among  black  fungi,  but  by  far  the  greater  number 
in  the  group  of  the  cup-fungi  and  the  disc-fungi. 

Kinds  of  lichens  in  Minnesota.  There  are  probably  some 
500  species  of  lichens  in  Minnesota,  and  the  total  will  rather 
exceed  this  estimate  than  fall  below  it  when  the  work  of  dis- 
covery is  completed.  Among  the  simpler  forms  are  a  number 


0,6  Minnesota  Plant  Life. 

of  little  circular  discolored  patches  found  on  bowlders  and  cliffs. 
In  the  centre  of  such  a  discolored  patch  are  scattered  the  irreg- 
ular-shaped fungus  fruit-bodies,  in  which  are  produced  numer- 
ous spores  incapable  of  germination.  In  rock-lichens  of  this 
sort  the  fruit-bodies  are  not  exactly  circular,  as  in  the  majority 
of  the  group.  The  algae  which  are  present  are  of  rather  higher 
types  than  in  some  of  the  more  complicated  lichens.  They  be- 
long to  the  class  of  bright-green  algae,  and  sometimes  branched, 
filamentous  algae  are  found  in  the  partnership,  while  at  other 
times  isolated  green-slime  cells  are  the  rule. 

Rock-lichens.  The  majority  of  rock-lichens  in  Minnesota  in- 
clude bright-green  algae  rather  than  blue-green,  and  the  fungus, 
when  it  fruits,  produces  a  circular  disc,  reminding  one  exactly 
of  many  of  the  cup-fungi.  The  centre  of  the  disc  is  often  va- 
riously colored,  red,  black,  yellow,  blue,  purple,  pink  or  dull 
green.  The  texture,  too,  of  the  lichen-body  differs  in  different 
kinds,  for  in  some  it  is  papery  and  thin,  while  in  others  it 
may  be  brittle  and  encrusted.  Again  it  may  be  leaf-like,  or 
gelatinous.  In  addition  to  the  closely  attached  forms  growing 
upon  rocks  are  certain  loosely  attached  varieties — one  very  con- 
spicuous species  being  held  by  a  delicate  stalk  at  the  centre,  and 
then  spreading  out  into  a  round  flat  structure  the  size  of  a  pond- 
lily  leaf  and  much  resembling  a  piece  of  leather.  Related  to 
this  form  on  rocks  is  a  kind  which  is  common  among  mosses, 
producing  a  broad  green,  leaf-like  expansion,  but  it  may  easily 
be  recognized  as  a  lichen  if  it  is  turned  over  to  reveal  the  white 
fungus-like  appearance  of  its  under  side. 

Reindeer-mosses.  Most  remarkable  of  the  lichens  is  the 
reindeer  moss  which  is  so  predominant  a  form  of  vegetation  in 
polar  regions.  There  are  a  large  number  of  different  species 
and  for  the  most  part  they  grow  upon  the  ground.  Reindeer 
moss  in  Northern  Minnesota  often  forms  patches  of  hemispher- 
ical shape  and  "as  large  as  a  bushel  basket.  Plants  of  this  size 
must  be  very  old,  possibly  over  a  hundred  years,  for  they  grow 
slowly  and  are  of  perennial  habits.  I  have  seen  them  most 
beautifully  developed  on  an  island  in  Lake  Saganaga,  where 
they  covered  the  soil  among  the  pine  trees  and  I  could  not  help 
remarking  that  they  seemed  to  be  as  old  as  the  pine  trees  above 
them,  indicating  what  is  rare  in  Minnesota,  that  the  island  had 


Minnesota  Plant  Life. 


97 


never  been  touched  by  fire.  Beside  these  large  reindeer  mosses, 
which  are  the  particular  kind  that  bear  that  name,  there  are  a 
number  of  small  relatives  common  along  roadsides,  on  clay 
banks  and  among  mosses  in  the  woods.  One  sort  is  called  the 
cigar-moss  by  children  because  of  the  flaming  red  ends  of  its 
branches,  while  another  might  be  mistaken  for  a  cup  fungus  on 
account  of  its  vase-like  form,  but  would  be  easily  distinguished 
by  its  grayish-green  tint. 


FIG.  38.— A  tuft  of  "reindeer  moss."  Natural  size,  2%  feet  in  diameter.  Age,  probably  over 
one  hundred  years.  North  shore  of  I<ake  Superior.  After  photograph  by  Professor 
Bruce  Fink. 

A  curious  thing  about  the  much-branched  body  of  the  rein- 
deer moss  is  this,  that  it  all  belongs  to  the  fruit-body  area  of  the 
fungus.  The  real  vegetative  body  is  a  flat,  rather  insignificant 
tract  below,  and  instead  of  developing  simple  discs  or  cups  upon 
the  surface  of  this  body,  it  is  the  habit  of  the  reindeer  moss  to 
form  much-branched  cups  which,  unless  one  observes  carefully 
their  elaboration,  would  scarcely  be  recognized  for  their  true 
significance. 

Lichens  are  of  much  economic  importance  in  the  polar  re- 
gions where  they  are  for  animals  and  even  for  man,  a  staple  arti- 


gS  Minnesota  Plant  Life. 

cle  of  diet.  Reindeer  moss  if  cooked  is  edible,  calling  to  mind 
the  blanc-mange  made  from  the  red  seaweed,  known  by  the 
name  of  Irish  moss  or  carragene,  and  previously  alluded  to. 
Some  also  of  the  gelatinous  lichens  are  edible,  but  none  of  them 
is  of  any  particular  importance  as  an  article  of  diet  in  Minnesota. 

Black-fungi-lichens.  A  very  few  lichens,  in  which  the  fungus 
partner  is  a  black  fungus,  are  known  to  exist,  in  Minnesota. 
They  could  not  be  recognized  by  their  outward  appearance  from 
certain  forms  of  the  disc-lichens,  but  their  fruit-bodies  are  little 
black  bottle-shaped  objects  in  which  the  spore-sacs  are  pro- 
duced, and  are  quite  different  from  the  open  plates  and  saucers 
of  the  more  common  varieties. 

Lichen  parasites.  The  study  of  lichens  has  been  confused 
by  the  presence  upon  their  bodies  of  numerous  kinds  of  parasitic 
black  fungi  which  really  have  no  connection  with  the  lichen 
whatever,  but  merely  come  to  attack  it  just  as  their  relatives  at- 
tack the  leaves  and  twigs  of  the  forest.  Yet  when  one  remem- 
bers that  a  portion  of  the  lichen  itself  may  be  a  black  fungus,  it 
will  be  seen  how  puzzling  might  be  the  presence  of  a  closely 
related  black  fungus  parasite,  and  it  is  not  remarkable  that  some 
of  these  parasites  have  been  described  as  true  fruit-bodies  of  the 
lichen. 

Lichen  partnerships.  Although  there  are  a  great  many  part- 
nerships in  the  plant  kingdom  there  is  no  group  of  organisms 
where  the  principle  of  partnership  has  been  carried  so  far  as  in 
the  lichens,  for  the  combination-structures  have  taken  forms 
under  the  stress  of  their  struggle  for  existence  that  neither  of 
the  two  component  elements  would  have  been  at  all  likely  to 
assume  if  living  independently.  The  reindeer  moss,  for  exam- 
ple, has  become  a  little  shrub,  while  the  "old  man's  beard" 
dangles  its  cylindrical  stems  and  branches  from  tamarack  bark 
much  as  if  it  were  a  plant  of  higher  degree,  and  the  flat  leaf-like 
lichens  which  live  among  mosses  spread  themselves  out  to  the 
sun  quite  like  some  of  the  flat  liverworts.  Indeed  there  arises  in 
lichens  a  physiological  division  of  labor  in  view  of  which  areas 
similar  to  those  in  higher  plants  must  appear.  The  outer  layer 
of  the  plant-body  is  made  up  of  fungus  elements  and  serves  as 
an  epidermis,  resisting  the  evaporation  of  moisture.  The  next 
layers  underneath  are  crowded  with  algal  cells  and  do  the  work 


Minnesota  Plant  Life.  gg 

of  starch-making  for  the  partnership.      The  central  layers  in 
cylindrical  lichen-bodies  are  of  a  fungus  character  and  perform 
the  office  of  conducting  moisture.     The  whole  double  organ- 
ism, then,  is  built  upon  the  same  physiological  plan  as  are  the 
higher  plants  and  has  work  to  do  which  neither  an  alga  nor 
a  fungus  living  by  itself  could  well  do  on  land.     It  is  true  some 
algae,  like  the  gulf-weed,  develop  leaves  and  branching  stems, 
recalling  in  their  appearance  the  higher  plants,  but  on  land  it 
would  scarcely  be  possible  for  an  alga  to  adopt  such  a  form, 
while  it  would  be  unnecessary  for  a  fungus,  having  no  leaf-green 
to  illuminate,  to  assume  structures  essential  to  the  requirements 
of  leaf-green  at  work.     But  when  the  two  organisms  have  been 
brought  together  into  a  partnership  it  becomes  possible  for  this 
partnership  to  assume  forms  and  structures  favorable  for  the 
illumination  of  leaf-green,  for  the  proper  protection  of  it  while 
at  work,  and  for  the  maintenance  of  a  sufficient  supply  of  water. 
Beetle-fungi.     The  group  of  plants  to  which  I  have  given 
here  the  common  name  of  beetle-fungi  is  so  remarkable  as  to 
deserve  separate  treatment.     In  structure  the  plants  are  extra- 
ordinarily unlike  any  other  fungi.     They  are  certainly  not  un- 
common in  Minnesota,  although  from  the  peculiar  places  in 
which  they  live  they  have  never  been  brought  in  by  collectors, 
and,  indeed,  I  have  seen  but  a  single  specimen  collected  within 
the  borders  of  the  state.     It  is  their  habit  to  attach  themselves 
by  a  tiny  disc  to  the  bodies  of  water-beetles  and  other  insects 
living  in  damp  places.     Some  varieties  of  them  are  occasionally 
to  be  found  attached  to  the  wing-cases  of  the  little  scurrying 
beetles  that  get  together  and  whirl  about  upon  the  surface  of 
quiet  water.     The  plants  resemble  tiny  brushes  of  camel's  hair, 
a  sixteenth  of  an  inch  in  length  or  less,  and  when  examined 
closely  they  have  been  found  to  be,  in  their  structure,  very  much 
like  the  red  algae.     Indeed,  they  might  almost  be  taken  for 
red  algae,  which  at  some  remote  time  had  contracted  the  habit 
of  obtaining  food  without  the  aid  of  leaf-green.     Yet,  in  the 
details  of  their  structure,  in  some  respects  they  widely  differ 
from  the  red  algae.     The  character  in  which  they  most  resemble 
the  red  algae  is  their  method  of  breeding.     Just  as  in  the  algae 
the  egg-cells  are  here  provided  with  slender  cylindrical  projec- 
tions upon  which  the  sperm-cells  fix  themselves,  thus  fecundat- 


ioo  Minnesota  Plant  Life. 

ing  the  egg  and  making  the  development  of  spores  possible. 
But  when  spores  are  formed  they  are  not,  as  in  red  algae,  pro- 
duced on  stalks,  but  in  sacs,  and  in  this  peculiarity  the  beetle- 
fungi  resemble  the  sac-fungi.  Taking  all  their  qualities  into 
account  it  may  safely  be  said  that  they  are  but  distantly  related 
to  the  rest  of  the  fungi  and  are  entitled  to  stand  in  a  group  by 
themselves.  More  than  a  hundred  and  fifty  of,  these  curious 
beetle-fungi  are  known,  most  of  them  from  America,  and  it  will 
reward  observers  in  Minnesota  to  search  for  them  on  the  bodies 
of  aquatic  insects  and  of  insects  living  in  damp  places. 


Chapter  XIII. 

Various  Kinds  of  Bacteria* 


The  story  of  the  bacteria  is  one  of  the  most  astonishing  that 
modern  science  has  had  to  tell,  and  although  they  are  the  small- 
est and  simplest  of  all  plants,  I  have  thought  it  best  to  devote  an 
entire  chapter  to  their  discussion; — so  many  are  the  ways  in 
which  they  touch  human  life.  In  these  days  almost  everything 
is  attributed  in  some  form  or  other  to  a  microbe,  and  when  the 
extraordinary  character  of  these  remarkable  plants  is  appre- 
ciated one  is  not  surprised  to  read  that  some  savant  has  dis- 
covered the  microbe  of  crime,  the  microbe  of  drunkenness  or 
the  microbe  of  insanity,  all  of  which  have  at  various  times  been 
heralded  by  the  newspapers.  While  crime,  drunkenness  and  in- 
sanity are  not  the  result  of  microbe  activity,  yet  microbes  actu- 
ally serve  in  a  number  of  capacities  which  at  first  sight  seem 
quite  as  impossible,  and  one  can  scarcely  blame  the  public  for 
believing,  as  it  does,  almost  anything  that  it  is  told  about  mi- 
crobes, or  for  going  to  the  other  extreme  and  believing  nothing 
whatever. 

What  a  microbe  is.  The  term  microbe,  meaning  "little  liv- 
ing thing,"  has  been  applied  to  some  organisms  which  are  not 
bacteria,  as,  for  example,  the  slime-mould-like  creature  which  is 
the  cause  of  malaria,  or  the  yeasts  which  have  already  been  de- 
scribed in  the  chapter  upon  the  fungi.  By  far  the  greater  num- 
ber of  microbes  are  bacteria,  and  bacteria  themselves  are  very 
lowly  plants  related  to  the  blue-green  algae,  and  to  be  consid- 
ered, perhaps,  as  forms  of  this  algal  series  which  very  long  ago 
abandoned  their  leaf-green  and  began,  like  the  fungi,  to  make 
their  living  in  other  ways. 

Classification  of  bacteria.  In  size  bacteria  are  the  smallest 
of  living  things,  the  least  of  them  being  less  in  diameter  than 
one  thousandth  of  a  millimeter,  so  that  three  hundred  of  them 
could  stand  side  by  side  across  the  dot  over  the  letter  "i."  Oth- 


IO2  Minnesota  Plant  Life. 

ers  of  the  group  are  comparatively  much  larger,  the  largest  be- 
ing barely  fifteen-thousandths  of  a  millimeter  in  diameter. 
Sometimes  they  cling  together  in  chains  or  threads  thus  becom- 
ing filaments  of  considerable  length.  In  form,  bacteria  are 
either  spherical,  ovoid,  cylindrical,  twisted  like  corkscrews,  or 
irregularly  shaped.  They  never  possess  leaf-green,  though  some 
of  them  are  capable  of  producing  coloring  substances  of  other 
kinds.  It  is  now  impracticable  to  group  the  bacteria  as  was 
done  years  ago  into  different  species  based  upon  form.  The 
older  students  called  a  spherical  bacterium  a  coccus,  an  ovoid 
bacterium  kept  its  name,  while  a  cylindrical-elongated  form  was 
called  a  bacillus ;  but  it  has  been  shown  that  one  and  the  same 
organism  may  successively  assume  the  coccus,  the  bacterium 
and  the  bacillus  shape.  To-day  it  is  more  common  to  classify 
them  physiologically,  and  there  are  recognized  the  following 
principal  groups,  not  including,  perhaps,  all  of  the  forms,  but 
excluding  only  the  unimportant  ones.  The  groups  are  as  fol- 
lows: 

A.  Disease-producing    bacteria:      Of   these   there   are    two 
classes;  those  producing  diseases  in  animals  and  those  produc- 
ing diseases  in  plants. 

B.  Ferment-producing  bacteria:     Of  these  there  are   four 
principal  classes;   those  producing  butyric  acid,  in  which  class 
are  included  most  of  the  bacteria  of  putrifaction ;    those  pro- 
ducing lactic  acid,  including  the  forms  which  make  milk  sour,  of 
which  there  is  a  great  variety;   those  producing  alcoholic  fer- 
mentation, like  the  yeasts;    and  those  producing  vinegar  fer- 
mentation. 

C.  Heat-producing  bacteria :     Sometimes  the  cause  of  spon- 
taneous combustion  of  cotton  waste  and  the  heating  of  ensilage 
and  hay. 

D.  Light-producing  bacteria:     To  which   is   attributed    in 
part  the  phosphorescence  of  the  ocean. 

E.  Color-producing  bacteria :     Including  a  variety  of  forms 
which  produce  different  sorts  of  coloring  substances. 

F.  Nitrifying  bacteria:     Which  fix  atmospheric  nitrogen. 

G.  De-nitrifying  bacteria :     Which  decompose  urea. 

H.   Sulphur  bacteria:     Which  produce  granules  of  sulphur 
in  mineral  springs. 

I.   Iron  bacteria :     Which  secrete  iron  rust  or  iron  ores. 


Minnesota  Plant  Life.  103 

Substances  formed  by  bacteria.  Before  presenting  in  de- 
tail an  account  of  some  of  the  principal  forms  under  each  of 
these  groups,  a  few  words  may  be  said  upon  the  general  physi- 
ology of  the  bacteria,  which,  if  thoroughly  comprehended,  will 
make  clear  how  there  may  be  a  fundamental  similarity  in  all  the 
apparently  dissimilar  processes  dependent  upon  bacterial  action. 
Bacteria  are  living  plant  cells.  As  such  they  need  food,  and 
absorb  it,  using  it  in  their  own  way  and  excreting  their  waste 
products  which  may  be  as  various  as  the  food  substances,  and 
the  methods  of  digestion.  The  waste  products  given  off  may 
be  solid,  liquid  or  gaseous ;  and  among  the  substances  excreted 
are  a  great  variety  of  organic  compounds.  From  an  economic 
point  of  view  the  most  important  waste  materials  of  bacterial 
nutrition  may  be  classified  in  three  groups:  i.  Organic  poi- 
sons; 2.  ferments;  3.  nitrates  or  nitrites.  For  the  moment, 
consideration  of  the  iron,  sulphur  and  de-nitrifying  germs  is 
omitted.  If  a  bacterium  secretes  some  poisonous  substance  in 
the  body  of  an  animal  or  of  man,  the  higher  organism  will  be 
poisoned  just  as  if  bitten  by  a  snake.  Disease-producing  bac- 
teria are  principally  those  forms  which,  entering  the  animal 
body,  grow  there,  nourish  upon  its  tissues  and  produce  poisons 
that  are  carried  into  the  blood  and,  when  in  sufficient  quantity, 
produce  death.  Plants  are  subject  to  such  bacterial  poisoning 
quite  as  much  as  animals.  Pear-blight  and  potato-scab ;  carna- 
tion disease  and  cucumber-rot  are  well-known  examples  of 
bacterial  plant  diseases. 

Ferments.  Ferments  are  peculiar  organic  compounds  which 
are  remarkable  for  their  property  of  initiating  changes  in  other 
compounds.  A  very  little,  for  example,  of  the  ferment  which 
is  capable  of  converting  starch  into  sugar,  if  put  into  a  starchy 
substance  will  transform  thousands  of  times  its  own  weight  of 
starch  into  the  form  of  sugar.  Nor  will  it  be  destroyed  in  the 
process,  for  it  seems  to  take  into  itself  the  starch  on  the  one  side 
splitting  off  sugar  on  the  other,  but  always  remaining  the  same 
although  it  produces  very  great  changes  in  the  substances  upon 
which  it  operates. 

Nitrogen  salts.  Nitrates  and  nitrites  are  salts  of  nitrogen 
which  are  demanded  by  most  higher  plants  as  indispensable  ar- 
ticles of  food.  Such  organisms  use  scarcely  any  of  the  free  nitro- 


IO4  Minnesota  Plant  Life. 

gen  of  the  atmosphere.  Further,  they  are  able  to  assimilate  am- 
monia but  sparingly,  and  such  a  nitrogenous  compound  as  urea 
is  almost  worthless  as  a  food.  Therefore,  in  three  great  fields 
of  interest  to  the  human  race,  bacteria  are  active ;  first,  as  causes 
of  disease  through  the  poisons  they  secrete;  second,  as  the 
sources  of  ferments  which  are  used  in  the  various  arts  of  brew- 
ing, wine-making  and  the  dairy,  not  to  mention  tanning,  cigar- 
manufacture,  and  a  variety  of  technical  processes  which  are  de- 
pendent upon  the  proper  control  of  ferment-bacteria;  third, 
as  fertilizers  of  the  soil,  where  they  live  in  countless  billions  and 
under  a  variety  of  conditions  play  their  part  in  fixing  the  nitro- 
gen of  the  atmosphere  in  the  form  of  salts  to  serve  as  food  for 
the  plants  of  forest,  field  and  plain. 

Energy  produced  by  bacteria.  It  should  be  remembered 
that  among  the  activities  of  living  things  not  only  are  there 
processes  which  result  in  the  production  of  particular  substances, 
but  sometimes,  also,  in  the  development  of  particular  forms  of 
energy.  Heat,  for  example,  is  a  form  of  energy  which  arises 
in  the  human  body,  as  a  result  of  its  vital  activity,  and  light 
arises  in  the  body  of  the  glow-worm,  in  many  fungi,  and  in  a 
large  variety  of  marine  animals.  It  is  not,  therefore,  astonish- 
ing that  heat  and  light  should  be  among  the  results  of  bacterial 
activity,  and  it  may,  therefore,  be  comprehended  how  two  such 
apparently  unrelated  phenomena  as  an  epidemic  of  smallpox  and 
the  phosphorescence  of  the  ocean  should  each  of  them  be  but 
the  results  of  bacterial  growth  and  nutrition.  In  the  one  in- 
stance, the  waste  products  formed  are  substances  belonging 
to  the  group  of  organic  poisons.  Secreted  in  the  body  they 
injure  its  tone  and  may  even  shatter  its  mechanism,  causing 
death.  In  the  other,  light  is  one  of  the  results  of  bacterial  ac- 
tivity, just  as  in  the  physiology  of  the  fire-fly,  and  when  innumer- 
able germs  are  floating  at  the  surface  of  the  ocean  they  may  give 
to  it  that  faint,  uniform  illumination  which  is  recognized  as  bac- 
terial phosphorescence — a  phenomenon  which  has  been  exactly 
reproduced  in  the  aquaria  of  laboratories  by  artificial  cultures 
of  light-producing  bacteria. 

Substances  and  forces  harmful  to  bacteria.  Bacteria  differ 
among  themselves  in  the  kinds  of  food  which  they  demand,  in 
the  nature  of  the  waste  products  which  they  produce,  and  in  the 


Minnesota  Plant  Life. 

varieties  of  substances  by  which  they  are  themselves  poisoned. 
Almost  all  of  them  are  incapable  of  existing  in  direct  sunlight. 
Hence  there  is  much  sound  scientific  basis  for  the  belief  that 
sunshine  is  healthful.  Bacteria  are  destroyed  when  subjected 
to  the  action  of  certain  chemicals — of  which  corrosive  sublimate 
is  the  strongest  germicide.  Next  to  this,  in  general  use,  is 
carbolic  acid,  an  excellent  compound  to  employ  for  disinfection, 
like  the  one  first  named ;  while  a  great  number  of  other  sub- 
stances may  be  used  in  the  destruction  of  bacteria.  One  of  the 
first  methods  resorted  to  in  the  history  of  the  world  was  the 
utilization  of  sulphur  fumes  by  the  ancient  Romans  to  prevent 
their  grape-juices  from  fermenting.  Singularly  enough  men 
learned  how  to  keep  bacteria  out  of  their  wine  long  before  they 
practiced  intelligently  the  important  hygienic  rules  for  keeping 
bacteria  out  of  themselves.  Formaldehyde  gas  is  a  strong  dis- 
infectant and  is  much  used.  lodoform  sometimes  advertised  as 
a  useful  germicide,  is  of  doubtful  utility. 

Not  only  is  it  possible  to  destroy  bacteria  by  sunlight,  and  by 
numerous  substances  such  as  corrosive  sublimate  and  carbolic 
acid,  but  in  various  other  ways,  principally  employed  in  labora- 
tories. The  application  of  heat  is  a  most  important  mode  of 
preventing  the  growth  and  development  of  bacteria,  and  is  es- 
sential to  many  processes  by  which  it  is  desired  to  destroy  or 
prevent  the  appearance  of  bacterial  life.  Electric  currents  may 
also  be  employed  and  are  said  to  be  in  use  in  some  distilleries 
abroad,  where  wine  is  permitted  to  flow  for  a  time  in  an  electric 
field,  thus  preventing  the  development  in  it  of  certain  germs 
which  might  be  harmful  to  its  flavor. 

If,  then,  it  be  kept  clearly  in  mind  that  bacteria  have  their 
definite  food  requirements,  their  characteristic  excreta,  solid, 
liquid,  and  gaseous,  their  enemies  and  their  poisons,  one  is  pre- 
pared to  comprehend  a  great  variety  of  technical,  hygienic,  surg- 
ical, medical,  agricultural  and  other  natural  facts,  which,  until 
the  behavior  of  bacteria  was  known,  could  scarcely  be  explained. 

Disease-producing  bacteria.  There  may  now  be  examined 
the  habits  of  some  forms  of  bacteria  in  each  of  the  groups  named 
above.  In  Minnesota  there  must  be  two  or  three  hundred  dif- 
ferent kinds  of  bacteria.  New  varieties  are  being  discovered, 
one  might  say,  every  day,  and  no  doubt  a  great  number  still 


IO6  Minnesota  Plant  Life. 

await  investigation.  But  of  the  disease-producing  group  there 
are  some  with  which  men  are  unfortunately  only  too  familiar.  I 
may  name  three  of  especial  interest,  and  valuable  in  the  illus- 
tration of  different  points.  The  diseases  known  as  consump- 
tion or  tuberculosis,  typhoid  fever  and  smallpox  are  certainly 
produced  in  the  human  body  by  three  distinct  species  of  bac- 
teria, known  respectively  as  consumption-bacteria,  typhus- 
bacteria  and  smallpox-bacteria.  The  contraction  of  any  of 
these  diseases  does  not  necessarily  follow  the  entrance  into  the 
body  of  the  bacteria,  for,  in  the  first  place  the  bacteria  may 
enter  in  a  weak,  non-virulent  condition;  in  the  second  place, 
they  may  be  destroyed  in  the  body  in  a  great  variety  of  ways 
before  they  can  develop  and  multiply  sufficiently  to  do  any 
harm ;  in  the  third  place,  they  may  find  the  body  in  a  state  which 
would  prevent  their  nourishment  so  that  they  would  die  of 
their  own  accord.  It  is  probably  true  that  men  frequently  take 
into  their  bodies  harmful  germs,  which,  under  the  beautiful 
police-system  of  the  blood,  are  snapped  up  by  the  white  blood- 
corpuscles  and  destroyed  before  they  can  accomplish  any  mis- 
chief by  their  poison-secreting  habits.  That  condition  of  the 
body,  in  whatever  way  it  should  be  explained,  under  which  bac- 
teria of  a  certain  disease  cannot  grow,  is  called  immunity,  and 
immunity  may  be  apparently  either  inherited  or  acquired.  Im- 
munity to  yellow  fever  seems  to  be  inherited  by  certain  classes 
of  people  living  in  the  tropics,  but  it  may  be  acquired  by  persons 
born  outside  the  tropics  after  they  have  passed  through  the  ex- 
perience of  acclimatization. 

Contagious,  infectious  and  invasive  diseases.  If,  however, 
one  is  not  immune  to  consumption,  typhus  or  smallpox,  and  the 
germs  of  one  of  these  diseases  enter  his  system,  and  multiply  too 
rapidly  for  the  white  blood-corpuscles  to  destroy  them,  then 
very  soon  what  are  termed  the  symptoms  of.  the  disease  begin 
to  appear  and  the  patient  has  the  disease,  or  rather,  the  disease 
has  him,  for  he  is  now  the  prey  of  an  invading  force  of  tiny  fun- 
gus parasites.  Here  a  distinction  must  be  made  between  three 
types  of  bacterial  disease  which  affect  animals,  and  are  known 
as  contagious,  infectious  and  invasive  diseases.  A  contagious 
disease  is  caused  by  a  germ  which  can  ordinarily  live  only  in  the 
body  of  the  diseased  animal  or  in  that  of  some  closely  related 


Minnesota  Plant  Life.  IO7 

form.  An  infectious  disease  is  caused  by  a  germ  which  may  feed 
and  develop  in  the  body  of  the  animal,  but  habitually  feeds  and 
develops  in  not-living  substances,  such  as  sewage,  river-water 
or  the  soil.  Both  varieties  of  germ  are  alike  in  one  respect,  that 
they  poison  the  body,  for  they  secrete  into  it  certain  substances 
known  under  the  general  name  of  ptomaines,  comparable  as  has 
been  before  said,  to  snake,  alkaloid  or  albuminoid  poisons.  An 
invasive  disease  is  produced  by  the  development,  in  the  body,  of 
a  germ  which  though  not  violently  poisonous  yet  causes  disease 
through  the  multiplication  of  the  bacterium  itself.  Smallpox  is 
an  example  of  a  contagious,  typhoid  fever  of  an  infectious,  and 
lumpy-jaw  in  cattle  of  an  invasive  disease,  though  the  germ 
which  causes  the  latter  is  scarcely  a  true  bacterium.  The  cow 
writh  lumpy-jaw  has  the  tongue  and  jaw  leavened  by  the  germ 
much  as  though  they  were  loaves  of  bread,  but  the  animal  is  not 
seriously  poisoned  and  does  not  generally  perish  as  quickly  as 
does  an  animal  when  attacked  by  some  fatal  infectious  or  con- 
tagious disease  like  Texas  fever,  anthrax  or  hog-cholera. 

Quarantine  and  sanitation.  It  is  apparent  that  between  con- 
tagious and  infectious  diseases — the  one  produced  by  what  is 
called  an  obligatory  parasite  and  the  other  by  what  is  termed  a 
facultative  parasite — demand  widely  different  hygienic  methods 
of  prevention.  Against  contagious  diseases  quarantine  is  the 
great  preventive,  for  if  the  person  who  is  diseased  can  be  kept 
by  himself  others  will  not  be  affected.  Against  infectious  dis- 
ease hygiene  is  the  great  preventive,  including  here  especially 
what  is  known  as  sanitation.  When  one  knows  that  dangerous 
germs  such  as  those  of  typhoid  fever  may  develop  and  multiply 
in  garbage  heaps,  in  sewage,  in  unfiltered  river  water,  in  neg- 
lected reservoirs,  in  badly  prepared  foods  and  stale  fruits,  he 
understands  the  importance  of  removing  his  garbage,  attending 
to  his  sewage,  boiling  his  water  and  taking  heed  to  his  kitchen, 
his  ice-box  arid  his  diet.  All  the  methods  of  modern  quaran- 
tine and  sanitation  are  intelligently  prosecuted  in  the  light  of 
an  increasing  knowledge  of  bacterial  lives  and  habits. 

Inoculation  and  vaccination.  Passing  from  simple  preven- 
tive measures  to  somewhat  more  complicated  procedure  it  be- 
comes necessary  to  consider  the  processes  known  as  inoculation 
and  vaccination.  Inoculation  is  a  name  given  to  the  intentional 
and  actual  transference  of  the  germs  of  a  disease  to  the  body, 


io8  Minnesota  Plant  Lift. 

and  this  under  such  conditions  of  general  health  that  it  is  hoped 
the  patient  may  contract  the  disease,  become  acclimated  to  it, 
so  to  speak,  and  thus  avoid  it  at  a  time  when  his  physical  state 
might  not  be  so  favorable  to  withstand  it.  In  the  old  days  this 
means  was  adopted  to  diminish  the  mortality  from  smallpox  and 
is  still  practiced  in  China.  Vaccination  is  a  jiame  given  to  the 
injection,  into  the  body,  of  a  mild  form  of  disease-bacteria; 
because  when  the  body  thus  becomes  acclimated  it  is  more  re- 
sistent  to  the  virulent  form.  The  remarkable  discovery  of  Jen- 
ner  that  cow-pox  was  a  mild  form  of  smallpox,  and  that  after 
vaccination  had  "taken,"  as  the  saying  is,  one  would  not  then 
easily  contract  the  malignant  disease,  was  the  precursor  of  other 
types  of  vaccination,  such  as  those  of  Pasteur,  who  vaccinated 
successfully  with  mild  anthrax  and  mild  hydrophobia,  thus  ren- 
dering the  vaccinated  individual  immune  to  the  more  virulent 
types  of  these  maladies. 

Koch's  lymph.  Quite  a  different  attempt  to  control  such  a 
disease  as  consumption  was  that  of  Koch,  whose  famous  lymph, 
a  few  years  ago,  was  much  exploited  in  newspapers  and  peri- 
odicals. It  had  been  known  for  some  time  that  the  bacteria  of 
consumption  could  be  cultivated  outside  the  human  body  upon 
a  variety  of  substances  such,  for  example,  as  beef-broth  jelly. 
Cultures  of  the  consumption  germ  were  made  in  this  way  by 
Koch,  and  by  means  of  glycerine  an  extract  of  their  poison  was 
prepared.  The  extract  of  poison  was  then  injected  into  the 
body — a  very  different  process  from  vaccination,  because  in  that 
case  the  germs  themselves  are  placed  in  the  body  of  the  patient. 
It  had  been  observed  that  the  consumption  bacteria,  like  other 
sorts,  produced  around  the  patches  where  they  grew,  excreta  to 
such  an  extent  that  they  poisoned  the  tissues  of  the  body  and 
limited  the  growth  of  their  own  colonies,  which  were  unable  to 
absorb  food  from  the  poisoned  tissue.  Thus  is  explained  the 
habit  of  the  consumption-germ  of  making  tubercles  in  the  lungs. 
It  was  Koch's  idea  that  he  could,  by  means  of  his  lymph,  poison 
the  lung-tissues  artificially,  not  enough  to  kill  the  patient,  but 
enough  to  prevent  the  bacteria  from  developing.  In  this  effort 
he  was  not  entirely  successful. 

Serum  therapy.  Another  and  more  hopeful  method  of  com- 
batting infectious  and  contagious  diseases  after  they  have  begun 
to  develop  in  the  patient,  is  supplied  by  the  process  known  as 


Minnesota  Plant  Life. 

scrum  therapy.  In  order  to  understand  this  it  must  be  noticed 
that  the  relation  between  bacteria  and  an  animal  which  they  are 
infesting  is  reciprocal.  Just  as  they  poison  the  organism  so  do 
certain  compounds  in  the  blood-serum  poison  them.  The  sub- 
stances generated  in  the  blood  and  poisonous  to  bacteria  are 
known  technically  as  anti-toxins.  Now  acclimatization  to 
germ  diseases  seems  to  be  in  part,  at  least,  due  to  a  develop- 
ment of  anti-toxins  in  the  blood-serum — that  is,  in  the  watery 
part  of  the  blood  in  which  the  corpuscles  are  suspended.  So  if 
a  horse  or  other  animal  be  acclimated  to  a  disease — diphtheria, 
for  example, — and  then  the  serum  from  such  an  animal  be  in- 
jected into  the  veins  of  a  patient  suffering  from  the  disease  in 
question,  a  supply  of  anti-toxins  is  put  in  a  position  where  it  can 
poison  the  disease  germs.  This  treatment,  indeed,  has  been  re- 
ported as  successful  for  diphtheria — so  much  so,  that  if  proper 
serum  is  quickly  obtainable,  even  a  malignant  case,  taken  in  its 
early  stages,  can  be  combatted.  A  time  may  be  expected  when 
anti-toxins  will  have  been  discovered  for  all  of  the  dangerous 
germ  diseases  which  kill  annually  so  many  hundreds  of  thou- 
sands of  the  human  race.  Serum-therapy  may  be  described  as 
a  sudden  acclimatization  of  the  blood  through  the  injection  of 
acclimated  serum  from  another  animal,  and  it  is  exactly  com- 
parable to  the  use  of  antidotes  for  ordinary  cases  of  poisoning. 
The  antidote,  however,  is  taken  directly  into  the  blood  and  not 
into  the  stomach. 

Diseases  of  animals  and  plants.  Not  only  are  men  subject 
to  a  large  number  of  bacterial  diseases,  but  also  domestic  ani- 
mals, birds,  fish,  tiny  water  insects  and  crustaceans,  or  even 
plants — and  among  the  latter  should  not  be  omitted  the  bacteria 
themselves,  for  it  is  well-known  that  some  varieties  are  so  in- 
imical to  others  that  they  may  produce  a  growth  which  will  de- 
stroy the  original  colony.  Plant  bacterial  diseases,  such  as  pear- 
blight,  potato-scab,  cucumber-rot  and  carnation-blight  are  not 
uncommon  in  Minnesota  and  considerable  damage  results  from 
their  activity.  No  highly  effective  methods  of  combatting  them 
have  as  yet  been  devised.  Plant-quarantine  against  infected 
plants,  plant-hygiene  and  sanitation  and  the  selection  of  resist- 
ant varieties  represent  about  the  extent  of  modern  treatment. 

Bacteria  of  putrifaction.  Among  the  ferment-producing  bac- 
teria, those  which  convert  organic  substances  into  compounds 


iio  Minnesota  Plant  Life. 

of  which  butyric  acid  is  an  important  member,  are  concerned  in 
the  processes  known  under  the  general  name  of  putrifaction. 
Sometimes  it  is  advantageous  to  distinguish  between  putrifac- 
tion and  decay,  both  of  which  may  be  bacterial  in  their  origin. 
When  an  organic  mass  putrifies  it  gives  off  offensive  odors,  but 
it  may  decay  without  such  odors  becoming  noticeable.  The 
offensive  stench  of  putrifaction  indicates  that  butyric  fermenta- 
tion is  taking  place  and  this  is  produced  by  bacteria  which  work 
in  the  absence  of  the  free  oxygen  of  the  air.  But  the  modifica- 
tion of  organic  bodies,  known  as  decay,  proceeds  when  there  is 
an  abundant  supply  of  free  oxygen  for  the  bacteria.  It  should 
be  noted,  however,  that  some  forms  of  bacteria  are  unable  to 
live  in  the  presence  of  free  oxygen,  while  others  are  as  depend- 
ent upon  its  presence.  The  odor  of  putrifaction  towards  which 
all  have  a  feeling  of  repulsion,  just  as  towards  a  snake  lying 
coiled  in  the  grass,  is  caused  by  volatile  ethers  or  ill-smelling 
gases  emanating  from  the  putrifying  mass.  Such  characteristic 
odors  are  instinctively  recognized  by  the  human  race  as  indica- 
tive of  danger— in  this  case  due  to  the  presence  of  bacteria.  In 
themselves,  it  is  difficult  to  understand  how  one  odor  should  be 
preferred  to  another,  but  experience  has  taught  to  some  extent 
what  odors  may  be  presages  of  danger  and  what  may  not,  hence 
that  natural  repulsion  when  one  is  brought  into  contact  with 
those  useful  and  necessary  changes  by  which  dead  bodies  are 
converted  into  materials  which  can  be  used  again  in  the  round 
of  life. 

Canning  of  fruits  and  other  technical  processes.  Various 
technical  processes  involve  a  control  of  the  germs  of  putrifac- 
tion. Among  many  examples  is  the  canning  of  fruits,  meats 
and  vegetables,  where  heat  is  applied  to  destroy  the  bacteria  and 
the  substances  are  then  sealed  up  in  such  a  manner  that  bac- 
teria cannot  gain  ingress.  Milk,  too,  is  sterilized  or  Pasteur- 
ized, and  preserved  in  bottles,  a  process  in  which  heat  may  be 
used,  or  chemicals,  notably  boracic  acid.  Other  processes  de- 
pendent upon  the  exclusion  of  putrifying  bacteria,  are  the  salt- 
ing of  meat  and  fish,  as  when  corned  beef  is  prepared  in  vats 
of  brine,  the  smoking  of  fish  practiced  by  the  Indians  in  Min- 
nesota, as  well  as  by  the  whites,  the  smoking  and  drying  of 
meats,  and  all  those  in  which  cold  is  used  as  a  preservative. 


Minnesota  Plant  Life.  1 1 1 

The  refrigerator  cars  and  cold-storage  warehouses  which  are 
such  important  features  of  modern  civilization,  making  it  pos- 
sible for  Minnesota  dressed  beef  and  dairy  products  to  be 
shipped  even  across  the  waters  of  the  Atlantic,  are  purely  de- 
vices for  limiting  the  growth  of  putrifactive  bacteria  by  keep- 
ing the  temperature  below  a  point  where  they  can  develop. 

Bacteria  in  tobacco-curing.  In  the  general  group  of  putri- 
factive fermentive  processes  should  be  mentioned  one  or  two 
which  are  not  precisely  like  the  others.  For  example,  the  "fla- 
vor" of  tobacco  and  cigars  is  largely  due  to  certain  waste  prod- 
ucts of  bacteria  grown  <upon  the  tobacco  while  it  is  being  cured. 
The  difference  between  a  "good"  cigar  and  a  "bad"  cigar  lies 
principally  in  the  curing  of  the  tobacco  from  which  it  is  manu- 
factured, and  that  is  an  operation  in  which  bacteria  take  part. 
A  technical  method  has  even  been  devised  by  which  the  Havana 
bacteria  have  been  cultivated,  and  it  has  already  been  applied 
upon  a  small  scale  to  tobacco-curing  in  Germany.  As  a  result 
of  this  process  German  tobacco,  not  at  all  the  best,  was  con- 
verted into  qualities  which  could  not  be  detected  by  experienced 
smokers  from  the  genuine  Havana. 

Tanning  and  retting  bacteria.  The  tanning  of  hides  is  an- 
other industry  which  is  dependent  upon  the  action  of  bacteria, 
and  likewise  the  separation  of  hemp  and  flax  fibres  in  the  vats 
where  they  are  macerated. 

Bacteria  in  the  dairy.  None  of  these  processes  is  so  im- 
portant to  Minnesotans  as  those  of  yet  another  line  of  industry 
in  which  bacteria  play  a  necessary  and  extraordinary  part.  I 
mean  the  dairy  industries,  for  the  successful  production  of  the 
best  butter  and  cheese  is  as  essentially  dependent  as  is  brewing 
upon  the  proper  control  of  bacteria.  Even  the  "June  flavor" 
of  butter  has  been  artificially  produced  by  careful  control  of  its 
bacterial  content,  while  in  one  word,  the  difference  between  the 
various  brands  of  cheese,  with  few  exceptions,  lies  in  their  bac- 
terial flora.  Edam,  Neufchatel,  Gorgonzola,  Camembert  and 
Roquefort  cheeses — distinct  from  each  other  in  consistency, 
flavor,  and  odor — largely  depend  for  these  qualities  upon  sep- 
arate kinds  of  bacteria,  which  easily  appear  in  the  "natural 
home"  of  each  kind  of  cheese,  because  under  such  conditions  of 
climate  and  soil  they  may  be  produced  in  cheese  without  artifi- 


1 1 2  Minnesota  Plant  Life. 

cial  inoculation.  But  a  cheese  made  in  Minnesota  may  be  in- 
oculated with  Edam  germs  or  Brie  germs,  and  if  the  control  of 
its  manufacture  were  as  perfect  as  that  which  has  been  attained 
through  the  researches  of  Pasteur  in  the  brewing  industry, 
there  would  be  little  difficulty  in  sending  out  such  choice  prod- 
ucts from  any  dairy  in  the  world.  Indeed,  in  Denmark,  where 
dairy  industries  have  reached  such  high  perfection,  pure  cul- 
tures of  Edam  bacteria  can  be  everywhere  obtained  and  Edam 
cheeses  can  be  manufactured  at  will.  The  flavor  of  the  cheese 
and  its  odor  come  largely  from  ethers  which  are  the  result  of 
bacterial  activity.  Since  certain  bacteria  produce  certain  ethers, 
it  is  evidently  necessary  to  keep  careful  control  over  the  growth 
in  the  cheese  and  through  failure  to  do  this,  highly  offensive 
odors  are  exhaled  by  the  cheeses  of  careless  dairymen.  This  re- 
sults from  putrifactive  germs  gaining  ingress  to  the  mass  and 
such  cheeses,  without  straining  the  language,  may  be  called  dis- 
eased. A  peculiar  form  of  diseased  cheese  is  the  blown  cheese 
in  which  gas-forming  bacteria  produce  bubbles  large  enough  to 
destroy  the  proper  texture  of  the  mass.  Cheese  may  also  be 
soured  by  the  presence  of  lactic-fermenting  bacteria,  as  well  as 
by  offensively-scented  and  undesirable  butyric  forms. 

Ripening  of  cheese.  One  is  now  in  a  position  to  under- 
stand the  various  processes  described  as  the  ripening  of  cheese. 
After  the  cheese  has  been  set  away  to  ripen,  and  during  this 
process,  there  is  opportunity  for  the  growth  of  desirable  bacteria 
and  moulds — for  some  kinds  of  cheese  such  as  Stilton,  are  de- 
pendent for  their  flavors  largely  upon  mould.  When  a  dairy  is 
manufacturing  bad  cheese  it  is  evident  that  the  "sanitation"  has 
been  poor,  or  that  quarantine  methods  should  have  been  adopted 
against  offensive  germs.  Hence  it  is  easy  to  understand  how 
necessary  is  cleanliness  in  the  dairy,  for  the  practice  of  cleanli- 
ness includes  both  quarantine  and  sanitation. 

Diseases  of  butter.  All  that  has  been  said  about  cheese  ap- 
plies equally  to  butter,  for  the  flavor  of  this  product,  including 
both  its  taste  and  odor,  is  dependent  upon  bacterial  activity. 
Diseases  of  butter  exist — of  which  rancid  butter  may  serve  as  an 
illustration. 

Diseases  of  eggs,  bread,  milk  and  cigars.  Many  other  arti- 
cles of  food  or  stimulants  may  be  diseased  in  the  sense  in  which 


Minnesota  Plant  Life.  i  { 3 

this  term  has  been  applied  to  cheese  and  butter.  Eggs,  for 
example,  while  still  in  the  body  of  the  fowl,  may  become  infected 
with  bacteria,  and  unless  used  within  a  short  time  after  they  are 
laid  they  become  stale  or  bad.  The  extremely  bad  smell  of  an 
egg  which  has  ptttrified  is  of  bacterial  origin  and  it  is  the  same 
little  plants  which  are  the  sources  of  the  gas  that  causes  the  bad 
egg  to  explode  when  cracked.  Bread,  too,  is  sometimes  af- 
fected with  diseases  through  which  it  becomes  sticky  or  ropy, 
and  milk  has  a  peculiar  tendency  to  bacterial  contamination. 
Milk  that  gradually  turns  blue  upon  standing,  or  that  gradually 
turns  red,  or  becomes  filled  with  mucus,  or  that  sours,  or  that 
curdles,  or  that  gives  off  offensive  odors,  is  generally  affected 
by  some  disease.  The  so-called  "turnip  odor"  of  milk,  popu- 
larly attributed  to  the  cow  having  eaten  turnips,  is  more  often 
of  bacterial  origin  than  connected  in  any  way  with  turnip  roots. 
Tobacco  is  generally  diseased  and  the  singularly  bad  cigars 
which  are  everywhere  encountered  should  be  regarded  as  the 
proper  prey  of  germs  and  be  made  objects  of  quarantine. 

Diseases  of  meat,  cheese,  vegetables  and  ice-cream.  Dis- 
eased canned  meats,  cheese,  vegetables  and  ice-cream,  not  in- 
frequently cause  death  to  persons  eating  them,  because  such  ma- 
terials sometimes  furnish  a  medium  for  the  growth  of  bacteria 
that  secrete  dangerous  poisons. 

Milk-souring  bacteria.  The  ferment-producing  bacteria 
which  have  been  hitherto  noticed  may  be  classed  under  the  gen- 
eral head  of  butyric-acid  ferment-producing  germs.  Another 
group  of  ferment-producing  germs  are  those  which  occasion  the 
composition  of  lactic  acid.  This  was- probably  one  of  the  first 
acids  known  to  the  human  race,  for  the  shepherds  of  pre-historic 
days,  wrhen  their  milk  turned  sour,  were  observing  the  result  of 
lactic  acid  fermentation  initiated  by  specific  germs.  To-day  the 
souring  of  cream  and  milk  may  be  brought  about  artificially  in 
the  dairy.  Most  butter-eaters  prefer  sour-cream  butters,  that 
is,  butter  made  from  cream  a  little  soured.  Just  as  it  is  now 
possible  immediately  to  separate  the  cream  from  the  milk  by 
centrifugal  machines,  without  waiting  for  it  to  rise,  so  is  it  pos- 
sible to  sour  it  by  inoculation  with  lactic  acid  germs  without 
waiting  for  spontaneous  infection  from  the  atmosphere.  Milks 

and  creams  soured  artificially  are  used  in  a  number  of  dairies. 
9 


U4  Minnesota  Plant  Life. 

Fermented  milk.  Together  with  yeasts,  there  are  lactic-acid 
fermenting  bacteria  employed  in  the  manufacture  of  the  fer- 
mented liquor  made  in  the  region  of  the  Caucasus  from  goat's 
milk  and  known  as  kephir.  In  Minnesota,  while  the  souring 
of  milk  is  a  natural  phenomenon  which  has  been  observed  by  all, 
I  am  not  aware  that  fermented  milks  are  commonly  produced. 

Milk-curdling  bacteria.  Different  from  the  souring  of  milk 
is  its  curdling,  which  takes  place  when  rennet  is  placed  in  it. 
Rennet  types  of  fermentation  may  be  initiated  by  bacteria,  al- 
though a  more  common  source  of  rennet  is  the  calf's  stomach. 

Souring  of  wine,  beer,  bread  and  ensilage.  Lactic  types  of 
bacteria  are  not  only  common  in  milk  but  in  wines  and  beers, 
so  that  in  the  brewing  industry  some  sorts  of  souring  which  beer 
undergoes  arise  from  lactic-acid  germs,  while  others  are  due  to 
vinegar-fermentation.  The  souring  of  bread  by  lactic  fermen- 
tation is  not  unknown  and  in  the  souring  of  ensilage  and  fodder 
the  activity  of  these  bacteria  is  ordinary. 

Vinegar-bacteria.  Still  another  type  of  fermentation  is  the 
vinegar-fermentation  by  which  sugars,  such  as  those  of  sweet 
cider,  are  converted  into  acetic  acid,  commonly  known  as  vine- 
gar. In  the  manufacture  of  vinegar  the  activity  of  these  bac- 
teria is  utilized  and  upon  their  growth  depends  every  art  in 
which  vinegar  is  employed.  Acetic  acid  ferments  may  originate 
also  in  beers  and  wines,  in  breads,  and  sometimes  in  fruit-jellies. 
The  bacteria  which  produce  the  ferments  are  not  all  of  the  same 
sort  but  are  of  several  different  kinds. 

Antiseptic  surgery.  One  very  important  special  technical 
process  is  largely  dependent  upon  the  control  of  various  fermen- 
tive  bacteria,  namely,  antiseptic  surgery.  The  precautions  which 
the  surgeons  take  in  entering  upon  an  important  operation,  are 
intended  to  prevent  the  ingress  of  putrifactive  or  other  fermen- 
tive  bacteria  into  the  wound  through  the  operation.  Hence  the 
carbolic-acid-spray,  the  heating  of  the  knives,  lint,  bandages  and 
sponges,  the  dress  devised  to  catch  as  little  dust  as  possible,  the 
cleanliness  of  all  utensils,  and  the  frequent  illumination  of  the 
operating  room  in  good  hospitals  by  sunlight.  With  the  suc- 
cess of  antiseptic  methods  it  has  been  discovered  that  pus  or 
"matter,"  as  it  is  popularly  termed,  is  not  an  unavoidable  con- 
comitant of  wound-healing.  Wounds  not  of  surgical  origin, 


Minnesota  Plant  Life.  i  i  5 

such  as  bullet-wounds,  commonly  undergo  bacterial  infection 
after  which  pus  forms  and,  in  serious  cases,  blood  poisoning  may 
follow.  With  the  increase  of  humanitarian  methods  in  warfare 
the  time  may  come  when  sterilization  of  bayonets  and  swords 
will  be  insisted  upon  under  the  laws  of  nations,  thus  diminishing 
the  mortality  from  wounds  in  battle.  To-day,  unless  it  were  for 
the  modern  knowledge  of  bacteria  and  their  habits,  surgery 
would  be  as  rough  and  ready  and  generally  fatal  as  it  was  a  hun- 
dred years  ago. 

Light-producing  bacteria.  Regarding  light-producing  and 
heat-producing  bacteria  there  is  little  necessity  to  add  anything 
to  a  mere  mention  of  their  occurrence  in  the  state.  It  is  true 
no  ocean  bounds  the  Minnesota  of  to-day  and  glows  during  the 
activities  of  light-producing  bacteria,  but  sometimes  upon  rotten 
logs  or  upon  damp  places  in  the  forest  a  faint  phosphorescence 
is  visible  which  may  be  attributed  to  the  presence  of  light-pro- 
ducing germs.  This  power  of  illumination,  however,  exists  in 
some  higher  fungi,  so  one  cannot  be  sure  that  the  dim  radiance 
of  decayed  logs  in  the  forest  is  due  to  bacteria  unless  a  careful 
examination  be  made. 

Heat-producing  bacteria.  The  heat-producing  bacteria, 
while  they  are,  like  all  the  rest,  invisible,  are  known  by  their 
works,  and  their  peculiar  habits  are  tacitly  recognized  by  the 
insurance  companies  which  send  inspectors  to  see  that  cotton 
wastes  and  refuse  are  not  allowed  to  accumulate  where  they 
might  be  ignited  by  "spontaneous  combustion."  The  impres- 
sion should  not  be  received  that  all  forms  of  spontaneous  com- 
bustion are  of  bacterial  origin.  Some  are,  however,  and  the 
power  which  bacteria  of  this  kind  have  of  raising  the  tempera- 
ture in  a  mass  where  they  are  growing  has  been  clearly  demon- 
strated. 

Color-producing  bacteria.  Turning  now  to  the  examination 
of  color-producing  bacteria  much  might  be  said,  for  this  is  a 
group  of  considerable  interest  and  importance.  In  the  middle 
ages  and  in  regions  where  science  has  not  yet  dispelled  the 
clouds  of  ignorance  and  superstition,  many  men  have  lost  their 
lives  on  account  of  the  appearance  of  red  bacteria  that  excited 
the  fears  of  those  who  saw  them.  The  phenomenon  of  ''blood- 
spots"  on  linen  which  has  been  lying  in  damp  places,  or  upon 


ii6  Minnesota  Plant  Life. 

bread  or  food-materials,  is  often  due  to  the  growth  of  bacteria 
with  the  power  of  secreting  a  red  dye.  When  such  spots  ap- 
peared, very  naturally,  upon  sacramental  bread  in  the  churches 
and  monasteries  of  the  Middle  Ages,  it  was  regarded  as  an  ex- 
tremely bad  omen,  and  this  same  phenomenon  in  earlier  times 
and  in  older  civilizations  was  no  less  terrifying.  Many  an  un- 
fortunate man  or  woman  has  been  seized  and  put  to  the  torture 
on  account  of  these  red  bacteria,  and  even  yet  their  presence  is 
regarded  with  superstitious  horror  in  most  parts  of  the  world. 
Besides  the  red  forms  there  are  those  capable  of  producing 
blue,  pink  and  yellow  dyes  which  are  alike  conspicuous.  Such 
growths  will  appear  "spontaneously,"  developing  from  atmos- 
pheric germs,  upon  the  surface  of  steamed  potatoes  kept  in  moist 
places  where  they  occur  as  more  or  less  flattened  hemispherical 
drops  of  colored  slime.  If  a  bit  of  slime  is  placed  under  a  power- 
ful lens  it  will  be  discovered  to  consist  of  unnumbered  millions 
of  tiny  bacterial  cells,  imbedded  in  a  common  jelly  of  their  own 
secretion.  The  shapes  which  such  little  masses  of  bacteria  take 
when  growing  upon  a  steamed  potato,  or  a  piece  of  bread,  may 
be  compared  with  the  tubercles  formed  in  the  lungs  in  cases  of 
consumption.  The  mass  of  bacteria  becomes  inclosed,  as  it  were, 
within  a  shell  of  its  own  excrement  and  may  be  thus  prevented 
from  extending  uniformly  and  continuously  over  the  surface  of 
the  potato. 

Purple  bacteria.  One  very  remarkable  kind  of  color-bacte- 
ria deserves  especial  notice  since  it  is  an  exception  under  the 
general  definition  of  fungi  given  above.  Such  bacteria  are 
known  as  purple  bacteria  and  they  have  the  ability  to  develop 
in  a  thin  layer  just  inside  their  cell-walls,  a  remarkable  organic 
substance  known  as  bacterial  purple.  It  has  been  found  that 
germs  provided  with  bacterial  purple  in  their  cells  are  able  to 
assimilate  carbonic-acid-gas  in  the  dark  as  well  as  in  the  light. 
The  number  of  such  germs  is  small,  but  they  are  of  extraordi- 
nary interest  because  their  behavior  is  similar  to  that  of  green 
plants  which  decompose  carbonic-acid-gas  in  sunlight  or  under 
the  electric  arc,  using  the  products  in  starch-manufacture.  Bac- 
teria with  bacterial  purple  are,  therefore,  independently  nour- 
ished plants  in  very  much  the  same  sense  that  green  plants  are, 
and  they  can  use  in  their  nutrition  much  the  same  simple  food 


Minnesota  Plant  Life.  !  \  j 

substances  which  will  suffice  for  plants  with  leaf-green.  It  is 
not  clear  why  bacterial-purple  is  limited  to  so  small  a  number 
of  tiny  and  fowly  organisms,  while  leaf-green,  which  does  much 
the  same  kind  of  work,  is  present  in  almost  all  of  the  types  of 
higher  vegetable  life. 

Nitrogen  bacteria.  Among  the  bacteria  described  as  nitri- 
fying, there  are  t\vo  principal  classes,  those  which  live  in  the 
soil  or  water,  and  those  which  associate  themselves  with  higher 
plants,  forming  a  chemical  partnership  that  suggests,  a  little, 
the  arrangement  between  the  lichen  fungus  and  its  algal  mate. 
Nitrifying  germs  which  live  independently  in  the  soil  or  water 
have  apparently  the  power  of  producing  chemical  changes,  as 
a  result  of  which  the  nitrogen  of  the  air,  or  of  ammonial  com- 
pounds, is  combined  with  minerals  in  such  a  way  as  to  pro- 
duce the  nitrogen  salts  called  nitrates  or  nitrites.  Bacteria 
of  this  character  are  found  in  guano  beds,  and  the  ripening  of 
guano  into  the  high  grade  of  fertilizing  material,  which  it  is 
known  to  be,  must  be  attributed  to  the  presence  of  nitrifying 
and  de-nitrifying  bacteria.  Germs  of  this  general  group  are 
found  in  Minnesota  in  old  manure  piles,  and  in  other  masses  of 
decaying  animal  substances  as  well  as  in  ordinary  loam. 

Bacteria  on  clover  roots.  Still  more  interesting  are  the  ni- 
trifying bacteria  which  join  forces  with  higher  plants  and  de- 
velop a  nitrogen-fixing  mechanism.  If  one  pulls  up  by  the 
roots  the  first  patch  of  clover  which  he  sees,  and  then  carefully 
washes  out  the  soil  and  examines  the  rootlets,  he  will  discover 
upon  many  of  them  little  irregular  nodules  the  size  of  a  pin- 
head.  Upon  cutting  open  one  of  these  nodules  and  applying  a 
suitable  magnification  it  would  be  seen  that  the  swelling  on  the 
root  was  caused  by  the  growth  in  its  tissues  at  that  point  of  a 
colony  of  nitrifying  bacteria.  Apparently  the  presence  of  these 
bacteria  is  recognized  by  the  plant  as  desirable,  for  an  apparatus 
known  as  infection-threads  is  produced  in  the  root-substance  of 
the  clover  and  prolonged  into  some  of  the  root-hairs.  Root- 
hairs,  with  infection-threads,  pick  up  from  the  soil  the  nitrifying 
germs  and  these  are  then  led  back  along  the  threads  to  the  inner 
tissues  where  they  develop  and  multiply  in  the  nodules.  A  plant 
like  clover,  possessing  such  nodules,  grows  very  much  more  vig- 
orously than  one  without  them  and  certain  interesting  agricul- 


n8  Minnesota  Plant  Life. 

tural  experiments  have  illustrated  this  fact.  In  Alabama,  for 
example,  clover  grown  under  conditions  where  the  nodules 
could  not  form,  produced  only  about  one-sixth  as  much  fodder 
to  the  acre  as  did  the  same  kind  of  clover  when  grown  in  such 
a  way  that  the  nodules  could  develop.  All  kinds  of  peas,  beans, 
alfalfas,  clovers,  vetches  and  other  pod-producing  plants,  are 
capable  of  producing  bacterial  nodules.  They  will  not  form 
them  if  planted  in  a  soil  where  no  bacteria  of  the  proper  kind 
exist  and  this  is  a  reason  why  clover  crops  fail  to  do  well  in  cer- 
tain regions  where  the  conditions  seem  outwardly  favorable. 
In  Germany  some  laboratories  have  produced  cultures  -of  nod- 
ule-forming bacteria,  which  they  supply  to  farmers  under  the 
trade  name  of  mtragin.  If,  now,  a  soil  in  which  nodules  would 
ordinarily  develop  poorly,  is  inoculated  with  nitragin,  the  clover, 
pea  or  bean  crop  will  grow  with  double,  triple  or  quadruple 
vigor.  Agriculturists  may  reasonably  look  forward  to  a  period 
when  the  soil  will  be  regularly  inoculated  for  a  variety  of  crops 
just  as  cheeses  are  inoculated  for  a  variety  of  flavors.  For 
these  remarkable  facts  the  explanation  is  not  far  to  seek.  Dur- 
ing their  life-processes  the  bacteria  are  able  to  fix  the  nitrogen 
of  the  atmosphere  and  develop  nitrogen  salts.  But  these  ni- 
trates and  nitrites  are  precisely  what  the  higher  plant  demands  in 
its  nutrition  and  it  seizes  and  assimilates  them.  What  is  for  the 
bacterium  a  waste-product  is  for  the  clover  a  food-product.  In 
return  for  a  supply  of  nitrogen  salts  developed  and  delivered  in 
its  root  area,  the  clover  affords  protection  to  the  bacteria  against 
desiccation  and  supplies  them  with  certain  of  its  waste  products 
for  use  in  the  bacterial  economy.  It  is  a  striking  fact  that 
after  a  crop  of  clover  with  nodules  has  been  harvested  there  are 
more  nitrates  and  nitrites  left  in  the  soil  than  there  were  when 
the  crop  began  to  grow,  and  this,  too,  notwithstanding  that  clo- 
vers use  themselves  a  considerable  quantity  of  these  salts. 

Bacteria  and  crop-rotation.  From  the  facts  above  presented 
it  is  possible  to  understand  how  the  technical  process  familiar  to 
farmers  and  known  as  "crop  rotation"  is  at  bottom  bacterial. 
After  nitrates  or  nitrites  have  been  exhausted  by  the  growth  of 
cereal  crops,  or  root-crops,  such  as  turnips  or  sugar  beets,  the 
soil  may  be  replenished  and  invigorated  by  the  growth  of  some 
pulse  crop,  such  as  beans,  peas  or  clover.  It  would  be  a  great 


Minnesota  Plant  Life.  iIO/ 

triumph  of  agricultural  science  if  enough  could  be  learned  about 
the  nodule-bacteria  and  their  habits  to  train  them  to  grow  upon 
wheat,  oats,  barley  or  rye.  The  problem  of  the  world's  food  sup- 
ply would  then  be  solved,  for  every  cereal  crop  under  such  cir- 
cumstances would  "do  its  own  rotating"  and  instead  of  impover- 
ishing the  soil  the  crop  taken  from  it  would  leave  it  in  a  better 
condition  than  before.  It  is  true,  plants  demand  a  variety  of 
other  substances  in  their  nutrition  than  salts  of  nitrogen,  but 
these  are  the  only  substances  which  are  not  present  everywhere 
in  almost  unlimited  quantities.  Silicon,  sulphur,  phosphorus, 
calcium,  potassium,  iron,  oxygen,  hydrogen  and  carbon  and  the 
other  elements  appropriated  by  plants  in  their  food-economy 
can  usually  be  delivered  in  adequate  quantities  and  in  assimilable 
form.  The  peculiar  inability  of  green  plants  to  make  any  use 
of  atmospheric  nitrogen  would  in  a  few  generations  put  an  end 
to  all  plant  and  animal  life  on  the  globe  were  it  not  for  the  ac- 
tivity of  nitrifying  germs  in  the  soil  and  water.  Through  the 
agency  of  these  the  store  of  nitrogen  salts,  from  which  plants 
can  absorb  the  nitrogen  they  need,  is  constantly  replenished  and 
the  successive  generations  of  life  are  permitted  to  continue  on 
the  earth. 

Other  root-tubercle  bacteria.  Plants  of  the  pea  family  are 
not  the  only  ones  that  develop  root  nodules  containing  nitrify- 
ing bacteria,  for  such  nodules  are  also  produced  upon  alders  and 
upon  a  plant  related  to  the  buffalo-berries  of  the  western  Minne- 
sota prairie.  Since  these  plants  are  not  cultivated  in  fields  their 
root-nodules  are  of  less  economic  importance  to  the  agricultur- 
ist. 

Bacteria  of  urine.  Of  quite  a  different  class  from  those  just 
treated  are  the  de-nitrifying  bacteria  which  play  an  important 
part  in  the  economy  of  nature  by  their  ability  to  decompose 
urea.  It  is  generally  known  that  urea  is  the  ordinary  form  of 
nitrogenous  waste  material  excreted  from  the  animal  body,  but 
this  substance  while  a  compound  of  nitrogen  is  not  available  for 
the  nourishment  of  green  plants  until  it  is  decomposed  and  re- 
combined  into  nitrogen  salts.  The  decomposition  of  urea, 
wherever  it  occurs,  is  ordinarily  accomplished  by  the  activity 
of  de-nitrifying  germs.  As  a  result  of  their  action,  ammonia 
appears  and  this,  again  further  reduced  in  complexity,  may  lib- 


I2O  Minnesota  Plant  Life. 

erate  free  nitrogen  to  the  atmosphere  of  the  soil — and  it  is  to 
be  understood  that  ordinary  soil  contains  a  considerable  amount 
of  such  gaseous  material  together  with  oxygen  and  carbonic- 
acid. 

Sulphur  bacteria.  The  sulphur  and  iron  bacteria  are  of  some 
economic  importance  from  their  growth  in  mineral  springs. 
Sulphur  bacteria,  when  present,  occasion  an  odor  of  decaying 
eggs,  revealing  the  presence  of  a  gas  known  as  sulphuretted 
hydrogen.  During  their  nutrition  granules  of  sulphur  are  de- 
posited in  their  cells  and  they  form  a  stage  in  that  round  of  life 
in  which  sulphur  waste  products  are  given  off  by  animals,  then 
are  broken  up  with  the  production  of  sulphur  granules  in  the 
bacteria,  which  upon  the  death  of  the  germ  may  be  re-combined 
into  sulphur  salts  and  in  this  condition  may  again  be  used  by 
green  plants  for  food.  Animals,  then,  directly  as  do  the  herb- 
devouring  species  and  indirectly  as  do  the  flesh-devouring 
forms,  make  use  of  the  substances  produced  by  green  plants  and 
the  waste  is  again  begun  and  the  process  repeated. 

Iron  bacteria  and  iron-ores.  Iron  bacteria  form  iron  pre- 
cipitates where  they  grow  and  assist  in  the  rusting  of  iron  in 
some  parts  of  the  world.  They  frequently  extract  iron-rust 
from  the  waters  of  springs  and  form  flocculent  red  masses  of  the 
oxide.  There  is  reason  to  suppose  that  the  masses  of  iron-ore 
in  Northern  Minnesota  upon  the  Mesaba  range  were  deposited 
there  by  the  activity  of  iron-bacteria,  living  in  the  warm  waters 
of  an  ancient  ocean.  We  may  imagine  such  a  primeval  sea,  hot 
like  the  geysers  of  the  Yellowstone,  its  waters  impregnated  with 
iron  and  furnishing  a  splendid  field  for  the  peculiar  activities  of 
the  iron-bacteria.  Living  in  such  an  ocean  for  thousands  of 
years,  as  they  may  have  done,  there  is  nothing  unreasonable  in 
attributing  to  them  the  deposits  of  iron  ore  which  during  these 
latter  days  are  being  mined  for  commercial  purposes. 

Manifold  relations  of  bacteria  to  man.  Enough  has  now 
been  said,  about  the  bacteria  of  Minnesota  to  justify  their  appel- 
lation of  most  extraordinary  plants.  It  seems  inconceivable  at 
first  thought,  that  iron-mining,  cheese-making,  phosphorescence 
in  the  forest,  the  tanning  of  leather,  the  rotation  of  crops,  the 
ripening  of  guano,  the  blight  of  pear-trees,  epidemics  of  typhoid- 
fever,  the  souring  of  milk  and  the  sacrifice  of  innocent  people 


Minnesota  Plant  Life.  121 

when  blood-spots  have  appeared  upon  the  shew-bread,  should 
all  be  various  results  of  bacterial  growth.  Such,  however,  is  the 
fact,  and  the  whole  may  be  comprehended  upon  returning  to 
the  statement  made  in  the  opening  of  the  chapter,  that  bacteria 
are  plants  needing  various  foods  and  forming  a  variety  of  waste 
products.  The  poisonous  ptomaine  produced  by  bacteria  in  ice- 
cream may  cause  the  death  of  an  entire  picnic-party ;  the  waste 
products  of  a  bacterial  population  of  some  ancient  ocean,  ag- 
gregated in  enormous  quantities,  may  furnish  work  for  thou- 
sands of  miners  and  lie  at  the  foundation  of  great  modern  in- 
dustries. 

In  this  brief  account  by  no  means  all  of  the  possibilities  of 
bacterial  habits  and  characters  have  been  exhausted,  but  enough 
has  been  said  to  open  up  this  most  fascinating  field  of  investiga- 
tion and  to  show  in  what  a  multitude  of  ways  bacteria  touch 
human  life. 


Chapter  XIV. 

Mosses  and  Liverworts  as  Links  Between  the  Algae  and  the 

Higher  Plants* 


The  plants  known  as  liverworts  and  mosses  constitute  a 
group  intermediate  between  the  algae  and  the  ferns.  They 
may  be  regarded  as  the  descendants  of  algae  which  at  some  re- 
mote time  in  the  past  climbed  slowly  out  of  the  water  and  es- 
tablished themselves  upon  the  land.  They  still  retain  a  number 
of  algal  characteristics,  although  they  have  naturally,  on  account 
of  their  terrestrial  habitat,  varied  from  the  structural  types  which 
were  characteristic  of  the  algae  themselves.  As  is  generally  the 
rule,  it  is.  during  their  early  stages  that  they  most  resemble 
algae.  All  mosses  and  liverworts  when  first  developed  from 
their  spores,  in  a  great  many  ways  recall  the  algae.  This  is 
especially  true  of  the  lower  group  of  liverworts. 

The  mosses  and  liverworts,  embracing  some  five  or  six  hun- 
dred Minnesota  species,  are  found  for  the  most  part  in  groups 
of  large  numbers  of  individuals,  for  they  are  essentially  social. 
A  moss-tuft  at  the  base  of  some  tree  or  in  some  crevice  of  the 
rocks  consists  of  hundreds  of  moss  plants  growing  very  close  to- 
gether and  possibly  all  derived  from  the  propagation  of  a  single 
original  individual  which  had  become  established  at  that  point. 
Many  of  them  prefer  moist  places  and  some  are  entirely  aquatic, 
floating  freely  in  the  water,  or  attached  to  pebbles  at  the  bottom 
of  the  lake  or  stream.  Under  such  conditions  they  might  pos- 
sibly be  mistaken  for  algae.  It  is  not,  however,  probable  that 
these  aquatic  mosses  or  liverworts  are  the  ones  most  closely 
related  to  the  algae,  although  such  a  supposition  would  seem 
reasonable.  On  the  contrary,  they  may  rather  be  regarded  as 
land  forms  which  have  returned  to  the  water  as  a  secondary 
adaptation ;  for  in  a  careful  study  of  the  plant  world  it  becomes 
evident  that  plants  in  the  history  of  their  development  have 
changed  their  habitations  more  than  once. 


Minnesota  Plant  Life.  I2* 

Mosses  are  abundant,  too,  in  very  dry  localities  and  are  found 
in  little  blackened  tufts  upon  the  bare  surfaces  of  bowlders  and 
cliffs.  Many  of  them  cling  to  the  bark  of  trees  occupying  posi- 
tions like  those  frequented  by  lichens.  Some  are  found  regu- 
larly at  the  bases  of  trees,  the  trunks  of  which  serve  as  concen- 
trators of  moisture;  for  when  the  rains  fall  upon  the  twigs  of 
trees  many  of  the  drops  are  conducted  along  the  branches  to  the 
trunk  ^of  the  tree  and  in  this  way  the  region  around  the  base  of 
the  trunk  becomes  more  moist  than  the  soil  at  a  little  distance. 
Having  taken  advantage  of  this  natural  irrigation-system  a  va- 
riety of  mosses  frequent  the  bases  of  tree-trunks.  The  kinds 
which  grow  in  such  positions  are  in  general  different  from  those 
growing  on  moist  cliffs  or  on  dry  bowlders,  or  in  swamps,  or 
mixed  with  grass  along  the  road-side  edge  or  in  fields,  or  on 
hillsides. 

Mosses  and  liverworts  are  distinguished  from  each  other  in 
a  variety  of  ways.  They  unite  in  having  a  young  stage  which 
resembles  the  plant-body  of  the  algae.  Upon  this  buds  are 
formed  that  develop  into  the  mature  moss  or  liverwort  plant. 
Liverworts  constitute  a  group  of  organisms  more  variable  than 
the  mosses.  They  show  more  types  of  structure  and  have  been 
described  as  Nature's  experiment-ground  from  which  the  higher 
plants  have  originated.  Two  groups  of  higher  plants  are  con- 
ceived to  be  improvements  of  the  liverwort  stock.  These  are 
the  mosses  (a  terminal  group)  and  the  club-mosses  or  Christmas- 
green  plants  which  gave  rise  to  the  ferns  and  pines.  Though 
they  are  of  somewhat  different  degree,  as  well  as  of  different 
kind  of  structure,  the  liverworts  and  mosses  may  well  be  con- 
sidered together.  Their  habits  and  habitats  are  much  the  same. 
In  most  instances  their  general  appearance  is  similar,  though 
there  are  some  liverworts  which  have  the  flat,  prostrate,  leaf- 
like  appearance  of  certain  lichens,  quite  different  from  the  leafy- 
stemmed  habit  of  the  mosses. 

Breeding  habits  and  life-histories.  All  of  these  plants  pro- 
duce true  eggs  and  spermatozoids.  After  fecundation,  the  egg 
develops  into  what  is  called  a  liverwort-fruit  or  moss-fruit.  But 
such  fruits  are  really  independent  organisms,  and  here  one 
meets  with  that  remarkable  fact  in  the  life  of  plants  technically 
known  as  alternation  of  generations, — a  phrase  which  means  that 


124  Minnesota  Plant  Life. 

each  alternate  generation  in  the  life-history  is  made  up  of  sim- 
ilar organisms,  while  the  generations  between,  although  similar 
to  each  other,  are,  in  structure,  entirely  dissimilar  to  the  alter- 
nating generations. 

The  life-history  of  a  liverwort  or  moss  is  briefly  as  follows: 
Inside  the  capsules — those  little  urns  which  rise  on  their  slender 
stalks  above  a  moss-tuft  —  large  numbers  of  spore-cells  are 
produced,  in  little  spherical  sacs,  four  spores  in  each  sac.  The 
sacs  lie  loosely  in  the  interior  of  the  developing  urn.  When  the 
urn  is  ripe  the  sacs  will  have  all  dissolved,  the  spores  will  have 
separated  from  each  other  and  in  the  form  of  a  fine  powder  lie 
loose  and  dry  within  the  urn.  In  mosses,  the  urn  in  most  in- 
stances has  a  lid  which  is  thrown  off  and  then  the  spores  are  free 
to  sift  out  over  the  neck  and  are  carried  away  to  places  favor- 
able for  their  germination.  The  variety  of  ways  in  which  mosses 
and  liverworts  arrange  to  scatter  their  spores  at  the  most  ap- 
propriate times  for  their  well-being  need  not  here  be  discussed, 
but  later  will  be  given  some  attention. 

When  one  of  the  spores  has  found  a  place  where  the  moisture 
is  sufficient  for  its  growth  its  wall  breaks  and  almost  always  a 
green  cell  is  protruded.  In  a  few  liverworts  the  spores  divide 
internally  into  a  little  group  of  cells  before  their  walls  break,  but 
in  most  species  this  is  not  common.  The  green  cell  grows  and 
divides,  building  either  a  little  flat  plate  of  cells,  reminding  one 
of  the  flat,  fresh-water-algae,  or  a  branching  thread,  reminding 
one  of  some  of  the  thread-algae.  In  any  case  not  all  of  the 
plant-body  of  this  young  moss  or  liverwort  is  green.  Some 
colorless  threads  are  produced  which  serve  as  root-hairs  for  ab- 
sorption and  attachment.  Such  an  immature  moss  or  liverwort 
plant  is  called  the  first-stage  of  the  moss.  The  first-stage  may 
continue  for  some  time  and  in  a  few  little  mosses  it  forms  a 
green  mass  of  creeping  threads  which  covers  on  clay  banks  a 
considerable  area.  Usually,  however,  the  first  stage  in  both 
mosses  and  liverworts  is  comparatively  small  and  transitory.  In 
peat  mosses  it  makes  a  difference  in  the  structure  of  the  first- 
stage  whether  the  spores  germinate  in  water  or  on  land.  When 
they  germinate  in  water  the  first-stage  has  been  known  to  take 
the  form  of  a  branching  thread,  but  when  they  germinate  011 
land,  the  first  stage  becomes  a  flattened  plant-body  half  an  inch 
or  more  in  length,  and  one  layer  of  cells  in  thickness. 


Minnesota  Plant  Life. 


If  mosses  proceeded  no  farther  in  their  development  than 
the  first-stage,  they  would  be  regarded  as  algae;  but  there  is 
the  capacity  in  all  of  them  to  develop  branches  upon  the  first- 
stage,  arising  from  little  buds  of  cells.  The  branch  which  thus 
arises  quickly  takes  the  form  of  the  mature  moss  or  liverwort 
and  is  known  as  the  second-stage,  or  mature  stage  of  the  sexual 
plant.  Sometimes  this  mature  stage  is 
itself  a  flattened  body  as  in  those  broad, 
forked,  green  plates  which  are  found  so 
commonly  on  the  damp  sides  of  ravines. 
More  often  the  second-stage  takes  the 
form  of  a  stem  upon  which  are  borne 
leaves.  In  liverworts 
this  stem  is  almost  in- 
variably quite  pros- 
trate, bearing  two  rows 
of  leaves,  right  and  left, 
and  a  third  row  of 
scales  on  the  under 
side.  Liverworts  of 
this  sort  are  therefore 
called,  in  common  par- 
lance, scale-mosses. 

In  the  moss  division 
of  the  general  group 
there  are  no  forms  in 
which  the  second-stage 
is  a  flat  forking  plate  of 
tissue,  but  without  ex- 
ception the  plant-body  FIG.  39.  A  male  moss  FIG.  40.  A  female  moss  plant. 

consists  of  a  leafy  stem,        plant    The,  spTn'       The  ***-*J&™  are  inclosfd 

*  anes  are  produced  in  in  the  tuft  of  leaves  at  the 

Sometimes  Unbraiiched,  clusters  at  the  end  of  tip  of  the  stem.     After  At- 

«   .,  .  the  stem.     After  At-  kinson. 

while  in  other  varieties       kinson. 

it  may  be  branched  in 

a  definite  manner,  often  with  some  of  the  branches  subordinated 

to  others,  building  up  a  fern-like  or  tree-like  branch-system. 

Very  often  this  leaf-bearing  branch-system  in  mosses  stands 

more  or  less  erect  and  then  the  leaves  are  generally  arranged 

around  the  stems  in  spirals  quite  as  in  higher  plants.     In  one 


126 


Minnesota  Plant  Life. 


variety  of  moss  in  Minnesota  the  stem  is  erect  and  there  are  but 
two  rows  of  leaves,  each  with  a  peculiar  crest  on  its  mid-rib. 
When,  on  the  other  hand,  moss  stems  are  prostrate  in  habit 
there  is  commonly  something  in  their  leaf-arrangement  or  in 
their  structure  which  indicates  that  they  were  not  always  pros- 
trate but  have  adopted  this  position  for  some  peculiar  reason. 
But  among  the  "scale-mosses" — those  liverworts  which  bear 
leaves  in  two  rows — there  is  nothing  in  the  structure  to  suggest 
that  they  ever  maintained  an  erect  position.  Therefore,  it  is 
possible  to  make  this  general  distinction  between  mosses  and 
liverworts;  that  liverworts  are  essentially 
prostrate  plants  and  that  mosses  are  essen- 
tially erect  plants  in  some  of  which  the 
prostrate  habit  of  growth  has  been  second- 
arily resumed. 

Of  whatever  sort  the  plant-body  may  be 
in  the  second-stage,  it  is  always  character- 
ized by  a  variety  of  functions,  of  which  the 
breeding-function  may  be  regarded  as  the 
most  important  and  secondary  to  that  the 
nutritive.  When  mosses  are  about  to  breed 
they  produce,  in  some  species  upon  the 
same  plant,  in  others  upon  neighboring 
plants — organs  of  two  sorts.  The  male 
structures  are  commonly  ovoid-cylindrical 
in  shape,  situated  sometimes  in  little  clus-  FIG.  4i.  The  c 
ters  at  the  ends  of  stems  and  surrounded 
by  leaves  of  slightly  different  color,  more 
purplish,  yellowish,  or  reddish  than  the 
ordinary  leaf.  Along  with  these  bodies, 

standing  on  their  short  stalks,  there  are  ordinarily  developed 
glandular  hairs  which  serve  to  keep  them  moist  by  retaining  a 
little  water  in  their  vicinity.  Each  ovoid  organ  consists  of  a 
layer  of  cells  surrounding  a  central  mass  of  small  cells,  several 
thousand  in  number.  Each  one  of  the  small  cells  is  capable  of 
producing  from  the  living  substance  of  its  interior,  a  single  sper- 
matozoid.  When  the  whole  organ  is  ripe,  the  end  opposite  the 
stalk  opens,  separates  or  dissolves  and  the  cells  of  the  interior 
are  squeezed  out.  Their  walls  liquify  and  a  horde  of  sperm- 


spermary  of  a  moss, 
much  magnified,  and 
two  spermatozoids,  very 
highly  magnified.  After 
Atkinson. 


Minnesota  Plant  Life. 


127 


cells  are  liberated  in  the  water  which  may  have  accumulated  as 
dew  or  rain,  or  is,  perhaps,  the  natural  habitat  of  the  plant. 
Each  spermatozoid  is  provided  with  a  pair  of  swimming  threads 
by  means  of  which  it  propels  itself  with  great  agility.  Mean- 
while upon  the  same  plant,  or  upon  neighboring  plants  of  the 
same  species,  there  have  been  developed  egg-producing  organs. 
These  arise,  mingled  with  glandular  hairs  upon  the  ends  or 
surfaces  of  branches  and  consist  at  first  of  solid  masses  of  cells, 
consisting  of  two 
well-marked  areas,  a 
spherical  base  and  a 
slender  neck  pro- 
t  r  u  d  e  d  outwardly. 
When  the  egg-pro- 
ducing organ  is  ripe, 
the  cells  at  the  end 
of  the  neck  separate 
from  each  other  and 
a  central  row  of  cells 
in  the  neck  turns 
into  mucilage  and 
oozes  out,  leaving  at 
the  bottom  a  large 
egg-shaped  cell  now 
inclosed  in  an  organ 
shaped  like  a  bottle 
with  a  long,  slender, 
hollow  neck.  The 
opening  from  the 

exterior  down  to  the  egg  is  produced  by  the  transformation  into 
mucilage  of  a  row  of  cells  as  has  been  described. 

Reproduction  of  mosses  and  liverworts.  All  mosses  and 
liverworts  produce  sperms  and  eggs.  Attracted  in  some  man- 
ner by  chemical  substances  dissolved  in  the  water  near  the  eggs, 
the  spermatozoids  find  their  way  to  the  mouth  of  the  egg-pro- 
ducing organ.  They  crowd  into  its  neck,  swimming  down  the 
canal  which  has  been  opened  for  them  until  they  reach  the  egg 
lying  at  the  bottom  of  the  flask.  One  sperm  more  active  than 
the  others,  or  first  upon  the  ground,  buries  itself  in  the  sub- 


FIG.  42.  Tip  of  a  leafy  moss  plant,  sectioned  lengthwise  and 
magnified.  The  flask-shaped  egg-organs,  one  with  an  egg 
in  place,  are  shown.  These  bodies  are  barely  visible  to 
the  naked  eve.  After  Atkinson. 


128  Minnesota  Plant  Life. 

stance  of  the  egg,  and  immediately  the  egg  forms  around  itself 
a  membrane  by  which  the  ingress  of  other  sperms  is  prevented. 
Such  an  egg  is  said  to  be  fecundated  and  in  a  short  time  it  di- 
vides by  a  cross-partition — in  a  direction  perpendicular  to  the 
long  axis  of  the  bottle  in  all  mosses  and  liverworts  with  the 
exception  of  the  horned  liverworts,  in  which  the  first  partition 
is  parallel  with  this  axis.  The  egg  now  consists  of  two  cells 
and  this  two-celled  body  is  reasonably  to  be  considered  as  the 
first-stage  of  the  embryo-plant  of  the  next  generation.  Such 
an  embryo  normally  develops  into  a  spore-producing  capsule, 
provided  in  some  species  with  a  long  and  slender  stalk,  but  in 
other  varieties  having  only  a  short  nub  of  sterile  cells  at  the 
base.  In  the  lowest  family  of  the  liverworts  there  is  no  stalk 
of  any  kind,  but  the  entire  matured  product  of  the  embryo  be- 
comes a  little  spherical  capsule  imbedded  in  the  tissue  of  the 
sexual  plant.  Whatever  may  be  its  structure  the  capsule  finally 
produces  spores.  The  function  of  a  moss  or  liverwort  capsule 
may  be  described  in  brief  as  the  production  of  as  many  and  as 
certainly  germinable  spores  as  possible.  In  high  types  of  moss- 
fruits  the  number  of  spores  rises  into  the  thousands,  while  in  the 
lowest  forms  of  liverwort-fruits,  the  number  of  spores  runs  from 
sixteen  to  sixty  four. 

What  is  meant  by  "alternating  generations."  It  is  evident 
that  there  exist,  in  the  moss  life-history,  two  plants  alternating 
with  each  other.  One,  the  sexual  plant,  has  two  phases,  the  im- 
mature or  first-stage  and  the  mature  or  second-stage.  The  first- 
stage  does  not,  except  in  one  kind  of  moss,  produce  the  organs 
of  sex,  and  in  this  peculiar  moss  it  is  not  the  egg-organs  but 
the  spermaries  that  are  formed  upon  it.  Therefore,  one  may 
describe  the  second-stage  of  the  moss  sexual  plant  as  a  repro- 
ductive branch  of  the  first-stage.  The  other,  the  capsular  plant  of 
the  life-history,  is  entirely  devoid  of  sex,  but  is  a  spore-produc- 
ing organism.  This  serves  to  illustrate  one  of  the  very  remark- 
able differences  between  higher  plants  and  higher  animals.  In 
higher  animals  a  fecundated  egg  develops  into  an  organism  like 
one  of  those  that  cooperated  in  the  production  of  the  fecundated 
egg,  thus  the  egg  of  a  fowl  develops  into  a  fowl,  and  the  egg 
of  a  fish  into  a  fish ;  but  the  egg  of  the  moss  does  not  develop 
into  an  organism  like  the  ones  that  cooperated  in  its  produc- 


Minnesota  Plant  Life.  j 

tion.  On  the  contrary,  it  develops  into  an  entirely  different 
creature,  in  the  body  of  which  there  may  be  produced  some 
thousands  of  spore-cells  and  each  one  of  these  if  planted  under 
favorable  conditions,  may  originate  a  new  first-stage  moss  or 
liverwort  plant.  Upon  one  of  the  first-stages  a  great  number 
of  buds  might  then  arise  initiating  the  second-stage  of  the  sex- 
ual form.  Thus  it  is  seen  that  while  animals  can  generally 
derive  but  a  single  individual  from  a  fecundated  egg,  mosses 

and   liverworts — and   higher  plants   still   more   strikingly are 

able  to  bring  into  existence  thousands  of  organisms  from  one 
egg.  The  only  thing  analogous  to  this  in  animals  is  the  phe- 
nomenon of  true  or  identical  twinning.  When  twins  are  of 
precisely  the  same  appearance  and  sex  it  is  believed  that  they 
have  developed  by  the  two  halves  of  the  embryo  in  its  youngest 
stage  separating  from  each  other.  Each  half,  relieved  from  the 
pressure  of  the  other,  develops  now  respectively  not  into  the 
right  or  left  half  of  the  body,  as  it  normally  would,  but  into  a 
separate  individual.  If  one  can  imagine,  not  twins  nor  quad- 
ruplets, but  great  numbers,  even  thousands  of  individuals  to 
arise  from  a  single  animal's  egg,  he  would  have  something  com- 
parable with  the  condition  in  plants  which  is  known  as  alterna- 
tion of  generations. 

The  origin  of  the  higher  plants.  In  the  light  of  what  has 
been  said  it  is  apparent  that  the  two  alternating  generations  in 
the  life-history  of  a  moss  or  liverwort  are  not  equivalent  to  each 
other,  and  one  of  them,  the  spore-producing  generation,  has 
no  analogue  in  the  life-history  of  those  animals  with  which  peo- 
ple are  familiar.  When,  in  the  algae,  an  egg  after  fecundation, 
instead  of  developing  at  once  into  a  new  organism  as  an  animal 
egg  does,  cuts  itself  in  two  into  a  pair  of  spores,  it  has  accom- 
plished normally  what  happens  accidentally  in  the  case  of  true 
twins.  It  seems  that  what  is  an  accident  among  animals  be- 
came the  rule  in  the  plant  world ;  so  in  other  algae  the  number 
of  spores  thus  developed  from  a  fecundated  egg  was  increased 
to  four  or  even  to  eight  in  the  sphere-alga.  Then  in  a  little  alga, 
the  disc-alga,  which  has  been  regarded  as  standing  closest  to 
liverworts,  the  number  of  spores  \vas  increased  to  sixteen ;  and 
for  one  fecundated  egg,  by  this  division  into  sixteen  spores,  the 
plant  was  able,  perhaps,  to  secure  sixteen  new  individuals,  pro- 


10 


130  Minnesota  Plant  Life. 

vided  that  all  the  spores  found  the  opportunity  of  germination. 
Such  little  clumps  of  spores,  originating  by  the  partition  of  a 
fecundated  egg,  then  underwent  a  division  of  labor,  so  that  the 
superficial  spore-mother-cells  acquired  the  character  of  capsule- 
wall-cells  and  did  not  ordinarily  retain  the  power  of  spore- 
production.  This  was  in  order  to  protect  the  cells  of  the  in- 
terior, which  remained  as  true  spore-forming  cells,  and  there  is, 
in  such  an  instance,  a  fundamental  peripheral  sterilization  of  the 
spore-mass,  so  that  it  comes  to  consist  centrally  of  functional 
spore-mother-cells  while  sterilised  spore-mother-cells  take  the 
character  of  wall  tissue.  Really,  by  this  time,  a  new  kind  of 
organism  has  come  into  existence,  something  entirely  unlike 
anything  in  ordinary  animal  life-histories. 

The  new  organism,  beginning  thus  simply  as  a  mass  of 
spores,  then  in  higher  types  assuming  the  form  of  a  mass  of 
spores  enclosed  in  a  wall,  underwent  further  improvement  in 
other  families  of  liverworts  and  mosses  until  finally  it  became 
a  large  capsule  with  long  slender  stalk,  several  layers  of  wall 
cells  and  a  supporting  column  of  sterile  cells  running  up  the 
middle.  By  means  of  such  improvements  the  possible  number 
of  spores  was  increased  and  they  were  better  managed  by  the 
plant ;  for  when  the  spores  of  a  moss  are  distributed  from  a  cap- 
sule on  a  tall  slender  stalk  they  will  fall  farther  on  every  side, 
thus  obtaining  more  favorable  chances  of  persistence  than  if 
scattered  from  a  short-stalked  capsule. 

To  the  philosophical  botanist  this  profound  need  of  coun- 
terbalancing the  unfavorable  conditions  of  the  environment 
suggests  itself  as  the  occasion  of  erect  habit  in  herbs,  shrubs 
and  trees.  By  maintaining  the  erect  position  plants  can  also 
enjoy  better  illumination ;  but  it  may  be  safely  assumed,  for  the 
reasons  that  have  been  given,  that  the  erect  position  and  the 
slender  habit  of  growth  of  the  moss-fruit,  based  as  it  is  upon 
an  instinctive  effort  to  enlarge  the  opportunities  of  spores,  is  the 
precursor  of  all  erect  habits  in  the  terrestrial  spore-producing 
areas  of  plants, — and  essentially  all  plant  shoots  are  spore-pro- 
ducing areas.  Pine  trees,  for  example,  develop  pollen,  a  form 
of  spores,  in  their  little  cones.  Roots  never  develop  spores,  and 
may  be  regarded  as  derivatives  of  that  original  end  of  the  cap- 


Minnesota  Plant  Life.  131 

sular  plant  which  was  nearest    the  sexual  plant  and  was  not 
thrust  up  for  the  purpose  of  scattering  the  spores. 

This  further  fact  next  presents  itself  for  consideration :  that 
among  the  higher  plants,  all  prostrate  forms  of  stems  arc  secon- 
dary; for  stems  must  originally  have  been  erect,  like  the  moss 
fruit-body.  Thus  it  is  not  surprising  to  learn  that  the  oldest 
forms  of  terrestrial  plants  were  of  the  forest  rather  than  of  the 
prairie  type.  This,  at  least,  is  the  conclusion  that  is  reached 
upon  a  study  of  the  most  ancient  plant-fossils  preserved  in  the 
rocks. 


Chapter  XV. 

Liverworts  of  Minnesota* 


Mud-flat  liverworts.  The  lowest  family  of  liverworts  is  char- 
acterized by  a  flat  and  prostrate  leafless  plant-body,  such  as  may 
be  seen  in  the  little  circular  forms  growing  upon  mud-flats. 
These  may  be  recognized  as  different  from  lichens  of  similar 
habit  by  their  bright  green  color  unmodified  by  any  tint  of  gray 
or  blue.  They  occur  as  discs  an  inch  or  so  in  diameter  and  are 
made  up  of  forking  flat  stems  seeming  to  radiate  from  a  com- 
mon centre.  The  upper  side  has 
a  spongy  look  which  is  caused 
by  the  existence  of  air-cham- 
bers in  the  plant-body.  At 
the  edge  of  the  disc  are  the 
ends  of  the  forking  branches 
and  each  of  these  is  notched, 
while  at  the  bottom  of  such 
notches  lie  the  growing-points 
of  the  branches.  The  tip  cells 
of  a  branch  do  not  divide  so 

fast  aS  the  Older  Cells  and  thus     FlG-  43-     Mud-flat  liverwort,  showing  method 

of  growth  and  branching.      After  Atkin. 

the  older  parts   protrude   be-       so,i. 
yond  the  true  tip.     This  ex- 
plains why  the  tips  of  all  the  branches  in  this  family  of  liver- 
worts are  notched. 

Floating  liverworts.  A  close  relative  of  the  mud-flat  liver- 
wort, of  which  there  are  several  different  species  in  Minnesota, 
is  the  floating  liverwort.  The  plant-bodies  of  this  variety  are 
found  in  ditches  and  small  pools  of  water.  Sometimes  in  lakes 
they  are  found  entangled  among  the  cat-tails  and  bulrushes 
along  the  water's  edge.  The  plant  consists  of  delicate  forking 
branches  of  a  bright  green  color,  sometimes  gathered  together 


Minnesota  Plant  Life.  133 

by  the  waves  into  masses  as  large  as  one's  fist.  The  branches 
are  ribbon-like  and  generally  not  more  than  a  sixteenth  of  an 
inch  wide,  but  they  may  be  an  inch  or  more  in  length.  It  is 
impossible  to  mistake  this  plant  for  an  alga  or  for  any  form 
of  duck-weed  if  one  observes  the  notch  at  the  tips  of  all  the 
branches.  The  three-pronged  duck-weed,  which  is  often  found 
with  it,  is  a  flowering  plant  and  may  be  recognized  by  the  con- 
vex ends  of  its  little  flat  branches  and  the  greater  breadth  of  the 
stem  in  comparison  with  its  extension. 

Swimming  liverworts.  Another  form  of  lower  liverworts  is 
the  swimming  liverwort,  which  might  be  mistaken  for  a  duck- 
weed since  it  much  resembles  it  in  habit.  It  is  its  custom  to 
float  in  large  patches  upon  the  surface  of  quiet  pools.  Each 
plant  dangles  from  its  underside  a  tuft  of  root  hairs  into  the 
water  thus  obtaining  special  absorptive  areas  and  counterpoises 
against  being  turned  upside  down  by  the  wind.  The  swim- 
ming liverworts  differ,  however,  from  duck-weeds  in  being 
somewhat  heart-shaped,  on  account  of  their  terminal  notch, 
while  duck-weeds  are  rather  oval  discs  or  shaped  something  like 
little  trefoils  as  they  lie  upon  or  in  the  water. 

Cone-headed  liverworts.  The  next  higher  family  of  liver- 
worts has  the  same  general  character  in  the  sexual  generation 
which  has  been  described  for  the  mud-liverworts  and  their  allies, 
but  the  plant-bodies  are  in  many  instances  larger  and  more 
perfected.  The  cone-headed  liverwort  is  an  example  of  this 
group.  It  spreads  out  its  broad  forking  branches  of  a  dark 
green  color  upon  logs,  cliffs  and  bowlders  in  wet  places.  Its 
surface  is  marked  by  diamond-shaped  areas  in  the  centre  of 
each  of  which  is  seen  a  whitish  dome-like  eminence  not  much 
larger  than  a  pin-point.  The  width  of  a  single  branch  is  from 
a  quarter  to  three-quarters  of  an  inch  while  it  may  be  several 
inches  in  length.  On  the  under  side  are  produced  numerous 
root-hairs  and  tiny  purple  scales  along  the  conspicuous  mid-rib. 
When  the  cone-headed  liverwort  is  fruiting,  there  will  be  ob- 
served during  summer  and  autumn  certain  green  cone-shaped 
branches  close  to  the  surface  of  the  flat  stem.  In  this  condition 
they  remain  throughout  the  winter,  but  in  early  spring  the  stem 
of  the  cone-headed  branch  elongates  into  a  pale  stalk  a  couple 
of  inches  in  height  and  about  a  sixteenth  of  an  inch  in  diameter. 


134  Minnesota  Plant  Life. 

In  two  grooves  along  the  stalk  root-hairs  are  produced.  The 
fruit-branch  now  resembles  in  outward  appearance  a  small 
green-headed  toadstool  attached  to  the  broad  flat  branch  below. 
In  the  cone-headed  liverwort  there  are,  apparently,  two  kinds 
of  branches,  the  ordinary  vegetative  and  the  special  repro- 
ductive branches  which  bear  the  capsules.  If  one  of  the  cone- 
heads  be  separated  from  the  main  stem  in  autumn  or  in  early 
spring,  it  will  be  found  that  imbedded  in  the  under  side  of  the 
cone  and  surrounding  the  cavity  about  the  stalk  lies  a  ring 
of  black  capsules  inclosed  apparently  in  the  tissue  of  the  cone. 
The  number  of  these  capsules  varies  from  three  to  eight,  not 
usually  exceeding  the  latter  number.  With  the  point  of  a  pin 
they  may  be  dissected  out,  if  the  little  cones  are  handled  with 
sufficient  care  and  tact.  Each  capsule  removed  from  the  tis- 
sues which  were  surrounding  it  will  be  found  to  show  over  most 
of  its  surface  a  dull  black  color.  But  at  the  end,  where  the 
pear-shaped  body  was  imbedded  most  deeply,  for  a  little  dis- 
tance the  color  is  green.  With  very  great  care,  by  the  use  of 
a  sharp  pin-point  it  is  possible  to  remove  an  exterior  membrane 
from  the  body  which  was  dissected  out  of  the  cone-head  and 
when  this  close  outer  membrane  is  separated  a  little  object  of  a 
shiny  black  color,  except  at  the  pointed  end  where  the  color  is 
bright  green,  will  be  obtained.  If  it  has  not  been  broken  in 
the  process  of  extraction  it  may  now  be  split  in  the  palm  of  the 
hand  and  a  brown  or  blackish  mass  of  spores  and  accessory  cells 
may  be  removed  from  the  interior.  The  shiny  black  capsule 
is  the  fruit-body  developed  from  the  liverwort  egg  and  consists 
of  a  small,  short  green  stalk  or  foot  and  a  larger  capsular  por- 
tion, the  whole  constituting  a  slender  pear-shaped  object  about 
a  sixteenth  of  an  inch  in  length. 

In  the  cone-headed  liverwort  and  in  all  its  allies,  mingled  with 
the  spores  in  each  capsule,  are  certain  very  curious  cells  with 
microscopic  spiral  bands  or  hoops  developed  on  the  inner  sur- 
faces of  their  walls.  These  cells  are  of  an  elongated  spindle- 
shape  and  their  spiral  bands  are  very  sensitive  to  moisture. 
When  placed  under  a  powerful  lens  and  moistened  by  the  breath 
these  cells  writhe  and  struggle  in  a  remarkable  fashion,  owing 
to  the  alternate  shortening  and  lengthening  of  their  spiral  bands. 
The  movement  is  not  a  vital  one,  but  purely  physical,  like  the 


Minnesota  Plant  Life. 


135 


warping  of  a  plank,  yet  it  serves  a  purpose  in  assisting  the  spores 
to  escape  from  the  capsule.  By  means  of  the  writhing  motion 
of  these  curious  cells  the  spores  are  separated  from  each  other 
and  are  not  permitted,  in  the  economy  of  the  plant,  to  fall  in 
an  inert  mass  at  one  place. 

In  its  stalked  capsule  and  in  the  development  of  these  elaters, 
as  the  writhing  cells  are  called,  the  cone-headed  liverwort  marks 
an  advance  in  its  spore-producing  generation  over  the  mud-flat 
liverwort ;  for  in  that  plant  and  its  immediate  allies  the  capsule 
had  no  stalk  nor  were  there  any  elaters  mingled  with  the  spores. 
In  the  sexual  generation  of  the  cone-headed  liverworts  there 
exist  a  variety  of  other  improvements  in  structure  over  the 
mud-flat  species.  The  plant-body  is  much  larger  and  more 
robust,  the  air-chambers  are  more  regularly  disposed,  giving, 
as  they  shine  through  the  skin  of  the  plant,  the  diamond-shaped 
marking  to  the  surface.  Each  air  chamber  has  a  central  dome 
of  colorless  cells  and  in  the  middle  of  each  dome  there  is  an 
opening  or  air-pore  which  serves  as  an  aperture  through  which 
an  interchange  of  gases  may  take  place  between  the  starch- 
making  cells  that  line  the  chamber — where  they  are  best  dis- 
played on  its  floor — and  the  outer  air. 

Another  improvement  is  observed  in  the  production  of  spe- 
cial branches  with  cone-shaped  heads  for  the  development  of  the 
egg-producing  organs.  In  the  mud-flat  liverwort  neither  these 
nor  the  spermaries  were  formed  on  branches  differing  in  any 
important  respect  from  the  ordinary  branches.  Therefore,  in 
the  mud-flat  liverwort  when  the  egg  had  developed  into  an 
embryo  the  spore-producing  capsule  found  itself  imbedded  in 
the  general  tissues  of  the  sexual  plant,  and  was  not  able  to  dis- 
tribute its  spores  until  the  stem  had  decayed.  But  in  the  cone- 
headed  liverwort  with  its  special  branches,  the  egg-producing 
organs,  when  their  eggs  had  been  matured,  fecundated  and  de- 
veloped into  embryos,  were  all  lifted  up  into  the  air  a  couple  of 
inches  or  so  by  the  elongation  of  the  slender  special  stem.  By 
this  means  the  ring  of  capsules  on  the  under  side  of  the  cone- 
head  gain  an  opportunity  to  scatter  their  spores  over  a  much 
wider  circle,  thus  adding  to  their  chances  of  germination  and 
growth.  In  order  to  eject  the  spores  the  tiny  green  stalk  of 
the  capsular  plant  elongates  a  little  just  before  the  capsule  opens, 


136  Minnesota  Plant  Life. 

thrusting  the  end  of  the  capsule  out  beyond  the  rim  of  the  cone. 
In  this  way  each  capsule  scatters  its  spores  under  much  more 
advantageous  conditions  than  were  possible  for  the  mud-rlat 
liverwort. 

The  spermaries  in  the  cone-headed  liverwort  are  produced 
upon    short   blunt   branches    arising   at    the    tips    of   ordinary 


FIG.  44.  The  umbrella-liverwort;  showing  the  prostrate  vegetative  body,  and  the  upright 
branches  on  which  the  egg-organs  are  borne,  and  where  later  the  capsular  plants  will 
be  found  perching.  After  Atkinson. 

branches,  but  seeming  to  grow  upon  their  surface  because  they 
are  somewhat  displaced  in  the  after-growth  of  the  whole  sexual 
plant-body.  A  cut  made  vertically  through  one  of  these  sper- 
mary  branches  would  show  a  large  number  of  ovoid  sperm- 
producing  organs  apparently  imbedded  in  the  general  surface 
of  their  special  branch. 


Minnesota  Plant  Life.  137 

Umbrella-liverworts.  Related  to  the  cone-headed  liverwort 
is  the  umbrella-liverwort,  growing  in  localities  similar  to  those 
favored  by  the  plant  just  described.  The  flat  stem  is  a  little 
smaller,  usually  not  of  so  dark  a  green,  with  somewhat  crumpled 
margins  and  less  conspicuous  diamond-shaped  areas  on  the  sur- 
face. In  this  species  the  special  branch  which  bears  the  ring  of 
capsular  plants  has  a  head  shaped  somewhat  like  an  umbrella 
with  thick  ribs  but  without  a  covering.  The  branch  bearing 
the  spermaries  is  larger  with  broader  top  than  in  the  cone- 
headed  liverwort,  and  after  the  spermaries  have  opened  to  re- 
lease their  sperm  cells  the  general  spermary-bearing  branch 
elongates. 

Purple-edged  liverworts.  In  still  another  liverwort  related 
to  the  two  described,  the  plant-body  is  still  smaller,  averaging 
about  a  quarter  of  an  inch  in  width  and  an  inch  or  two  in  length, 
but  distinguished  by  the  same  flat  prostrate  habit  of  growth,  the 
same  notched  branch  tips  and  the  same  little  diamond-shaped 
areas  upon  the  upper  surface.  This,  from  the  color  of  the  mar- 
gins of  its  flat  branches,  may  be  called  the  purple-margined 
liverwort.  Its  special  erect  stems  are  shorter  and  more  delicate 
than  in  the  varieties  before  mentioned.  The  head  which  bears 
the  capsular  plants  is  rather  flat,  of  somewhat  square  outline, 
and  usually  supports  but  four  of  the  spore-producing  capsular 
plants  of  the  life-history. 

Besides  these,  which  are  among  the  commonest  forms  in  the 
state,  there  are  a  few  others  related  to  them  but  less  likely  to  be 
encountered. 

Cuplets  and  gemmae  of  the  umbrella-liverwort.  The  um- 
brella-liverwort just  mentioned  is  remarkable  among  species 
native  to  Minnesota  for  its  production  of  curious  tiny  propaga- 
tive  branches  clustered  together,  a  score  or  more  in  a  group, 
at  the  bottoms  of  little  cups  from  a  sixteenth  to  an  eighth  of  an 
inch  in  diameter  and  borne  upon  the  upper  surface  of  the  sex- 
ual plant-body.  These  little  cups  have  a  bottom  composed  of 
a  layer  of  cells  some  of  which  bulge  out  from  the  general  surface 
and  divide  into  a  stalk-  and  a  head-cell.  The  head-cell  then 
produces  a  small  convex  organ  shaped  somewhat  like  a  pair  of 
watch  crystals  placed  with  their  concave  surfaces  together  and 
notched  at  the  sides.  Such  bodies  are  called  gemmae.  They 


138 


Minnesota  Plant  Life. 


may  be  regarded  as  little  two-forked  branches  modified  by 
the  pressure  of  their  mates  in  the  cup,  into  the  bi-convex  form 
which  they  have  assumed.  Growing  among  such  gemmae  at 
the  bottom  of  the  cup  are  a  number  of  mucilage-hairs  which 
produce  a  slime  capable  of  swelling.  By  this,  as  soon  as  they 
mature,  the  gemmae  are  lifted  from  their  stalks  and  hoisted  over 
the  edge  of  the  cup.  They  are  then  carried  away  by  rain-water, 
or  by  currents  if  the  plant  is  living  in  a  ditch,  to  other  places 
suitable  for  the  growth  of  umbrella-liverworts.  It  makes  no 
difference  which 
side  of  a  gemma 
falls  toward  the 
ground.  The  un- 
der side,  after  the 
gemma  has  fallen 
into  position,  pro- 
duces root  -  hairs 
which  attach  it  to 
the  soil  and  the 
upper  side  begins  w 
the  development 
of  air  -  chambers 
while  the  whole 
branch  increases 
in  size.  In  this 
manner  the  plant 
is  abundantly 

propagated  without  the  intervention  of  eggs,  sperms  or  spores. 
Another  way  in  which  liverworts  propagate  is  much  more  anti- 
quated than  the  gemma-method  and  probably  suggests  the  origin 
of  gemma-propagation.  As  the  general  plant-body  grows  and 
forks,  the  branches  may  become  separated  from  each  other  by 
the  dying  away  of  parts  behind  the  forks.  Thus  ordinary  branches 
are  isolated  and  if  carried  to  a  distance  they  may  behave  very 
much  as  gemmae  do.  Ordinarily,  however,  they  remain  attached 
to  the  soil  and  serve  to  propagate  the  plant  only  to  adjacent  por- 
tions of  the  sub-stratum.  The  gemmae  may  be  regarded  as 
tiny  portable  propagative  branches  and  the  apparatus  for  sepa- 


FIG.  45.  Stem  of  the  umbrella-liverwort,  showing  the  little  cups 
with  bodies  inside,  which  are  employed  by  the  plant  for  pur- 
poses of  propagation.  After  Atkinson. 


Minnesota  Plant  Life.  I^Q 

rating  them  from  the  floor  of  the  cup  in  which  they  are  pro- 
duced may  be  regarded  as  a  special  improvement  of  the  dying- 
away  processes  which  served  to  separate  the  unmodified  larger 
branches.  The  wall  of  the  cup  may  be  considered  to  be  a  pro- 
tective layer  of  cells  originating  in  earlier  forms  as  a  mere  collar 
or  ring  and  perfected  in  the  umbrella-liverwort  into  the  little  cup 
or  vase.  Such  small  cups  with  their  inclosed  propagative  bod- 
ies are  the  result  of  considerable  improvement  over  earlier  and 
cruder  devices.  In  a  liverwort  known  as  the  crescent-cup  liver- 
wort, the  cup  in  which  the  gemmae  occur  is  not  circular  in  out- 
line but  is  shaped  like  a  crescent  moon.  Most  liverworts  do 
not  produce  such  cups  with  gemmae  growing  from  their  bot- 
toms, but  are  dependent  rather  upon  their  reproductive  pro- 
cesses or  upon  the  crude  type  of  propagation  in  which  ordinary 
branches  separate  from  each  other. 

The  livenvorts  which  have  been  mentioned  are  related  more 
or  less  closely  to  each  other.  They  fall  naturally  into  two 
series,  a  lower,  in  which  the  capsule  has  no  stalk  and  a  higher, 
in  which  very  short  stalks  are  developed  that  do  not,  however, 
elongate  to  any  considerable  degree  in  any  of  the  species. 

Horned  liverworts.  Quite  a  different  kind  is  the  horned 
liverwort,  plants  of  which  without  doubt  occur  in  all  sections 
of  Minnesota,  but  have  been  collected  in  but  one  or  two  local- 
ities. The  sexual  plant  is  a  flat,  somewhat  irregular-shaped, 
green,  prostrate  stem  devoid  of  leaves.  It  lies  upon  decaying 
timber  or  mud  and  forms  circles  which  have  not  the  bright, 
fresh  green  color  of  the  mud-liverwort  but  are  of  a  duller  and 
darker  hue.  From  the  upper  side  of  the  plant-body  spring 
slender  horn-like  projections  which  may  become  an  inch  or 
more  in  height.  These  horns  are  the  capsular  fruit-bodies  of 
the  plant  and  are  developed  from  eggs  produced  in  egg-organs 
imbedded  in  the  upper  surface  of  the  flat  green  stem.  It  is  a 
peculiarity  of  the  capsular  plant  in  this  kind  of  liverwort  that 
it  never  fully  matures.  It  consists  of  a  somewhat  bulbous  foot 
which  is  inclosed  in  the  green  prostrate  stem  and  above  the 
region  of  the  foot  are  layers  of  cells  which  continue  to  divide, 
constantly  forming  new  capsular  tissue,  so  that  the  capsule  may 
be  said  to  grow  from  the  base.  The  capsule  consists  of  a  wall, 


140  Minnesota  Plant  Life. 

more  than  one  layer  of  cells  in  thickness,  and  a  central  column 
of  cells  giving  strength  and  support  to  the  whole  structure. 
Between  the  central  column  and  the  wall  is  the  area  where  the 
spherical  spore-mother-cells  develop.  Each  of  these  is  capable 
of  forming  its  group  of  four  spores.  Mixed  with  the  spore- 
mother-cells  are  some  rather  crude  elaters  which  play  their  part 
in  the  distribution  of  the  spores  somewhat  as  did  the  more 
mechanically  perfect  elater-cells  in  the  cone-headed  liverwort 
and  its  allies.  When  the  capsule  of  the  horned  liverwort  is 
ripe,  it  splits  longitudinally  through  its  whole  length  and  the 
two  dry  halves  twist  about  each  other  and  about  the  little  col- 
umn of  the  centre  now  exposed  as  a  thread.  By  the  twisting- 
movement  of  the  two  halves  of  the  capsule  the  distribution  of 
the  spores  is  facilitated. 

This  kind  of  liverwort  is  extraordinarily  interesting  to  bot- 
anists because  it  seems  to  be  a  connecting  link  between  the 
liverworts  and  the  club-mosses.  The  horned  liverwort  differs 
considerably  from  the  cone-headed  liverworts,  the  mud-liver- 
worts and  their  allies,  in  the  character  of  its  capsular  plant.  As 
will  be  seen  from  the  description  this  is  of  higher  structural 
rank.  A  greater  proportion  of  its  substance  is  sterilized,  that 
is,  not  dedicated  to  the  production  of  spores,  while  in  the  um- 
brella-liverwort the  only  sterile  portion  of  the  plant  was  the 
wall  and  the  short  stalk  or  foot.  In  the  horned  liverwort  there 
exists  in  addition,  a  central  column  of  cells  making  possible,  by 
the  support  which  it  gives,  the  development  of  a  much  larger 
capsule  containing  many  more  spores.  Furthermore,  with  its 
indeterminate  growth  the  capsule  continues  and  is  not  com- 
pleted, as  were  simpler  forms  of  capsular  plants,  after  a  certain 
definite  number  of  cell  divisions.  In  this  capsular  plant  one  ob- 
serves the  first  tendency  of  such  an  organism  to  become  peren- 
nial. In  all  other  liverwort  capsular  plants  there  is  aimed  at, 
in  the  development,  a  definite  and  finished  structure,  and  when 
the  capsule  has  been  once  matured  there  is  no  further  growth. 
Under  such  conditions  it  is  not  possible  for  a  capsular  plant  to 
arise  capable  of  maintaining  itself  from  year  to  year.  The 
horned  liverworts  do  not  really  produce  perennial  capsular 
plants,  but  they  indicate  how  in  the  asexual  generation  perennial 


Minnesota  Plant  Life, 


141 


plants  might  easily  have  originated ;  and  it  is  believed  that  club- 
mosses  are  actually  to  be  compared  with  such  perennial  cap- 
sules. While  it  is  one  of  the  rarer  Minnesota  liverworts,  the 
horned  variety  is  of  peculiar  interest  and  should  be  sought  by 
amateurs  in  all  parts  of  the  state.  It  is  very  easily  recognized 
by  its  peculiar  habit.  The  only  plants  likely  to  be  mistaken  for 
it  are  certain  kinds  of  reindeer  moss  in  which  similar  slender 
horns  are  developed  from  a  flat  prostrate  body.  But  these, 
like  all  lichens,  can  be  easily  distinguished  by  the  gray  or  blue 
tint  which  is  given  to  the  plant  by  the  fungus  element.  Be- 
sides, the  erect  horn-like  bodies  of  the  reindeer  mosses  do  not 
split  and  are  of  course  not  capsules  at  all  but  erect  portions  of 
a  fruit-body  bearing  little  propagative  granules  over  their  sur- 
face or  giving  rise  to  superficial  discs  made  up  of  sacs  and  sterile 
threads. 

Leafy  liverworts  and  their  allies.  The  higher  division  of  liver- 
worts is  represented  in  Minnesota  by  a  considerable  number  of 
species.  Some  of  them  are  very  much  like  the  lower  forms  in  the 
habit  of  the  vegetative  body,  while  others  are  more  moss-like, 
consisting  of  branched,  prostrate  leafy  stems.  These  higher  liver- 
worts are  divided  into  two  series,  those  in  which  the  plant-body 
is  flat  and  leafless  constituting  one  division  and  those  in  which 
a  leafy  stem  is  maintained  constituting  the  other.  All  agree, 
however,  in  the  general  character  of  the  capsular  plant,  and  this, 
when  it  matures,  stands  erect  upon  the  surface  or  at  the  tip  of 
some  branch  of  the  vegetative  plant.  It  is  provided  with  a 
slender  stalk  which  is  usually  of  a  translucent  green  tint,  dif- 
ferent in  appearance  from  the  brown  or  red  stalks  of  most  moss 
capsular  plants.  At  the  end  of  the  pale  green  stalk  is  produced 
a  black  spherical  capsule  which,  when  ripe,  generally  splits  from 
the  tip,  making  four  flaps  that  turn  back  to  permit  the  escape 
of  the  spores  and  elater-cells.  Plants  classified  as  higher  liver- 
worts are  often  found  upon  the  bark  of  trees  or  upon  moist  soil. 
\Yhen  growing  upon  the  smooth  bark  of  the  birch  they  make 
delicate  green  traceries,  in  their  general  appearance  reminding 
one  slightly  of  the  sea-weeds.  They  do  not  form  little  tufts  as 
mosses  would  in  such  positions  but  remain  so  tightly  pressed 
to  the  surface  upon  which  they  grow7  that  it  is  difficult  to  re- 


142  Minnesota  Plant  Life, 

move  them  without  breaking  their  stems  in  pieces.  In  such 
liverworts  it  is  not  the  stem  of  an  egg-organ-bearing  branch 
that  elongates  to  assist  the  spores  in  their  dissemination  but  the 
true  stalk  of  the  capsule,  showing  that  the  plant  has  developed 
in  the  spore-producing  generation  itself  the  structures  requisite 
for  assistance  in  spore-distribution.  Unlike  the  horned  liver- 
worts, the  capsules  in  this  group,  which  are  commonly  spherical 
in  form  and  considerably  smaller,  do  not  need  and  accordingly 
do  not  develop  a  central  column  of  supporting  tissue,  but  the 
entire  cavity  of  the  capsule  is  occupied  by  the  spores  and  elaters. 

A  peculiar  thing  about  the  vegetative  plant  in  many  of  the 
higher  liverworts  is  the  production  of  two  lobes  in  the  leaf,  one 
of  which  is  turned  under  the  other.  The  one  turned  under  and 
facing  the  lower  side  of  the  prostrate  stem  is  sometimes  modi- 
fied into  a  little  pitcher  and  is  then  called  a  water-pocket  because 
it  serves  to  retain  moisture  that  in  drouths  the  plant  might  find 
serviceable.  In  such  little  water-pockets  on  the  under  sides  of 
certain  liverwort  leaves  tiny  worms  often  make  their  homes. 
It  is  difficult  to  see  how  they  can  be  of  any  great  advantage  to 
the  liverwort,  but  they  are  so  invariably  present  in  some  species 
that  there  must  be  a  partnership  arrangement  between  the  plant 
and  the  worms  which  dwell  upon  it.  In  the  water-pockets,  too, 
there  are  often  found  colonies  of  simple  algae  which  avail  them- 
selves of  the  small  drop  of  water  to  grow  and  develop.  In 
certain  exotic  species  the  water-pocket  becomes  a  trap  which 
catches  small  insects,  as  bladderworts  do. 

A  very  great  variety  of  leaf-forms  characterizes  the  leafy 
liverworts.  Sometimes  the  leaves  are  flat  and  scale-like,  hence 
the  name  of  scale-mosses  which  is  commonly  applied  to  plants 
of  this  group.  Again  the  leaves  are  slender  or  dissected  into 
fine  teeth,  and  they  may  even  become  modified  into  little 
branching  green  bristles,  which  look  quite  unlike  an  ordinary 
leaf.  In  the  tropics  such  leafy  liverworts  dispose  themselves 
upon  the  leaves  of  larger  flowering  plants  and  often  make  char- 
acteristic patches  of  vegetation  where  there  is  an  abundance  of 
moisture.  The  greater  number  of  kinds  in  Minnesota  display 
themselves  upon  the  bark  or  upon  damp  soil  along  with  mosses 
from  which  they  are  not  at  first  very  easy  to  distinguish.  They 


Minnesota  Plant  Life. 


143 


may  be  regarded  as  a  special  development  of  the  liverwort  type 
and  among  them  are  found  the  greatest  variety  of  plant-bodies 
anywhere  in  the  liverwort  group,  as  well  as  the  large  majority 
of  liverwort  species. 

None  of  the  liverworts  is  of  any  particular  economic  impor- 
tance, but  they  are  all  of  great  scientific  interest  on  account  of 
their  intermediate  position  in  form,  structure  and  development 
between  more  primitive  oceanic  types  of  vegetation  and  later 
terrestrial  types. 


Chapter  XVI. 

Mosses  of  Minnesota* 


The  mosses  may,  like  the  ferns,  be  conceived  to  be  the  de- 
scendants of  ancestral  forms  somewhat  similar  to  the  horned 
liverworts,  although  none  of  them  are  to-day  very  close  in  their 
structure  and  life-histories  to  that  group  of  plants.  All  mosses 
are  distinguished  by  the  following  peculiarities,  in  which  they 
differ  from  liverworts.  The  second-stage  of  the  vegetative  sex- 
ual plant  is  in  every  instance  a  branched  or  unbranched,  leaf- 
bearing  stem.  While  it  is  sometimes  prostrate  in  habit  this 
position  is  an  adaptive  one  and  not  original,  as  among  the  liver- 
worts. Finally  and  most  important,  the  young  capsular  plant 
before  maturity  always  bursts  the  wall  of  the  egg-organ  in  which 
it  began  to  develop  and  never,  like  most  liverwort  capsular 
plants,  matures  while  still  within  that  membrane.  A  moss 
capsular  plant  is  decidedly  a  creature  of  more  complicated  struc- 
ture than  a  liverwort  capsular  plant  and  it  consists,  even  in  the 
simple  forms,  of  a  generally  greater  number  of  cells.  There 
are,  however,  one  or  two  mosses  in  which  the  capsular  plants 
are  greatly  reduced  in  size,  and  these  would  scarcely  come  with- 
in the  general  rule. 

Mosses  have  acquired  the  ability  to  live  in  much  drier  places 
than  liverworts  are  accustomed  to  frequent,  indicating  their 
stronger  adaptation  to  terrestrial  life.  While  the  rock-dwelling 
liverworts  are  found  usually  on  moist  cliffs  or  banks,  it  is  not 
uncommon  to  find  some  mosses  growing  upon  the  driest  bowl- 
ders, where  a  little  crevice  or  hollow  in  the  stone  gives  them  a 
soil  upon  which  their  rootlets  may  work.  Such  mosses  are  gen- 
erally of  a  blackish  green  color  and  look  very  crisp,  crumbling 
easily  if  rubbed  with  the  fingers.  Yet  in  this  condition  they  are 
not  dead;  for  if  moistened,  they  rapidly  revivify  and  proceed 
with  their  functions  of  growth.  Other  mosses  choose  very  wet 


Minnesota  Plant  Life. 


145 


localities.  One  variety,  the  river-moss,  is  a  common  aquatic 
plant  in  Minnesota,  forming  slender  tufts  of  delicate  leafy  stems, 
attached  to  pebbles  and  rocks,  on  river-bottoms,  in  rapids  or  in 
pools.  Besides  this  particular  species  of  aquatic  moss,  there 
are  a  number  of  others  which  have  the  same  habitat. 

Peat-mosses.  The  peat-mosses  belong  to  the  lowest  family 
and  are  in  some  instances  aquatic.  They  are  familiar  objects 
in  the  tamarack  swamps  of  Minnesota,  where,  if  undisturbed, 
they  may  produce  hemispherical  patches  usually  of  a  gray 


FIG.  46.     Road  across  a  peat-bog;  tamaracks  and  birches  in  background.     Near  Grand  Rapids. 
After  photograph  by  Mr.  Warren  Pendergast. 

color  but  often  shaded  with  a  purple,  yellow  or  red,  and  rarely 
of  a  bright  grass-green.  They  are  peculiar  for  their  power 
of  absorbing  water,  and  this  they  do  by  means  of  special 
water-reservoir  cells  which  are  mingled  with  the  green  cells  of 
the  leaves.  Indeed  the  water-reservoir  cells  form  the  principal 
bulk  of  a  peat-moss  leaf,  while  the  starch-making  cells  are  dis- 
posed over  them  or  between  them  in  a  delicate  green  network. 
The  stems  and  branches,  too,  are  covered  with  layers  of  such 
reservoir-cells  so  that  if  a  tuft  of  peat-moss  is  wrung  in  the  hands 
water  can  almost  always  be  squeezed  out  as  from  a  sponge, 
ii 


146  Minnesota  Plant  Life. 

The  peat-moss  vegetative  plant  consists  of  a  central  axis 
upon  which  are  produced  lateral  leaf-bearing  branches  of  two 
kinds.  Some  of  them  protrude  at  an  angle  from  the  axis  and 
upon  these  the  leaves  contain  leaf-green  and  are  the  starch- 
making  areas  of  the  plant.  Others  with  pale  leaves  hang  limply 
down  along  the  axis,  covering  it  and  acting  as  conservators  of 
moisture.  The  leaf-bearing  branches  commonly  stand  very 
close  together  forming  a  terminal  tuft,  and  towards  the  end  the 
axis  itself  is  sometimes  branched  repeatedly.  At  the  very  tips 
of  the  branches,  especially  when  they  are  young,  a  red  or  purple 
dye  often  stains  the  leaves  and  the  surface-layers  of  the  stem. 
This  is  a  warming-up  color  and  is  useful  as  a  device  for  raising 
the  temperature  around  the  delicate  cells  of  the  growing  buds. 

Formation  of  peat-bogs  and  coal.  Peat-mosses  are  inher- 
ently social  plants  as  are  the  rest  of  their  group,  and  they  often 
occupy  large  areas  to  the  almost  total  exclusion  of  other  kinds 
of  plants,  except  certain  cranberries  and  heaths,  pitcher-plants, 
cotton-grasses  and  orchids  which  are  to  be  sought  in  peat-bogs. 
Every  year  the  axes  of  the  plants  increase  in  length  and  the 
older  stems  of  former  years  sink  lower  into  the  bog.  In  this  way 
the  centre  of  bogs,  especially  those  fed  by  springs,  becomes  often 
much  higher  than  the  circumference.  Such  raised  peat-bogs 
have  been  studied  in  New  Brunswick  and  occur  also  in  St.  Louis 
county,  Minnesota.  In  such  formations  while  one  must  ascend 
to  pass  from  the  edge  to  the  centre,  yet  the  texture  of  the  bog 
becomes  looser  as  the  margin  is  left  behind.  When  peat-moss 
has  been  growing  thus  for  many  centuries,  filling  what  was  once 
perhaps  a  lake,  the  remains  of  the  old  stems  become  matted 
together  by  the  pressure  of  the  heavy  water-logged  fresh  areas 
above  and  after  a  time  such  a  mass  becomes  compacted  into 
what  is  known  as  peat — probably  one  of  the  stages  in  the  pro- 
duction of  coal.  It  is  by  no  means  certain  that  coal  was  devel- 
oped from  mosses  like  the  living  peat-mosses,  but  it  is  alto- 
gether certain  that  it  originated  in  ancient  swamps  by  the  same 
general  process  which  is  to-day  building  the  peat-bogs.  So,  some- 
what as  iron-bacteria  deposited  beds  of  iron  ore  in  ancient  warm 
oceans,  mosses  and  other  plants  in  the  illimitable  swamps  of  the 
coal  age  contributed  their  part  to  modern  human  industry. 


Minnesota  Plant  Life. 


147 


Fruiting  habits  of  peat-mosses.  Peat-mosses  are  in  such  a 
favorable  position  for  simple  propagation  by  the  development 
of  branches  which  become  separated  from  each  other  upon  the 
death  of  the  older  portion  of  the  stem,  that  they  rarely  fruit  at 
all.  Sometimes,  however,  whole  bogs 
will  be  found  in  fruit  at  one  time. 
The  fruit-body  is  a  little  egg-shaped 
black  capsule  with  bulbous  base,  the 
whole  shaped  somewhat  like  a  dumb-bell 
with  one  end  larger  than  the  other  and 
a  short  neck  between.  The  smaller  end 
of  the  dumb-bell  is  imbedded  in  the 
enlarged  cushion-like  tip  of  a  slender, 
erect  leafless  branch  of  the  vegetative 
plant.  Around  the  bottom  of  the  cap- 
sule may  be  found  a  thin  broken  mem- 
brane which  is  a  relic  of  the  wall  of  the 
egg-organ  in  which  the  capsule  began  its 
existence.  Peat-moss  capsules  open  by 
little  circular  lids  which,  when  the  cap- 
sule is  ripe,  separate  from  the  bowl-part, 
allowing  the  spores  to  escape.  It  will 
be  observed  that  for  the  elevation  of  the 
spores  the  same  general  contrivance  is 
adopted  by  peat-mosses  that  appeared 
earlier  in  the  umbrella-liverworts  and 
their  allies.  The  slender  stem  which  lifts 
the  capsule  into  the  air  is  not  a  portion 
of  the  capsular  plant  as  in  the  "scale- 
moss"  liverworts  and  the  other  mosses; 
but,  as  in  the  umbrella-liverwort,  it  is  a 
portion  of  the  vegetative  plant  special- 
ized  for  the  purpose  of  elevating  the  cap- 
sule.  When  peat-moss  spores  germinate 

they  develop  under  ordinary  conditions  a  flat  plate-like  first- 
stage,  but  rarely  this  first-stage  arises  as  a  branching  filament. 
The  first-stage  usually  persists  for  weeks  or  even  months,  sel- 
dom, however,  becoming  very  large  and  in  no  case  exceeding 
an  eighth  of  an  inch  or  so  in  length.  Upon  the  first-stage,  buds 
form  which  mature  into  the  ordinary  peat-moss  plants  upon 


ded  at  the  tips  of  short  ieaf- 

less  erect    branches.     After 

Atkinson. 


148  Minnesota  Plant  Life. 

which  the  microscopic  organs  of  sex  arise.  The  sperm-pro- 
ducing organs  are  spherical  with  long  slender  stalks  and  arise 
in  the  axils  of  the  leaves.  The  egg-producing  organs  are 
formed  upon  the  tips  of  certain  branches  and  in  each,  as  is  the 
rule,  a  single  egg  is  produced,  and  this  when  fecundated  may 
segment  into  an  embryo  which  in  time  matures  into  the  cap- 
sular  plant  of  its  species. 

Granite-mosses.  Another  group  somewhat  related  to  the 
last  are  the  granite-mosses — representatives  of  which  may  pos- 
sibly grow  upon  granitic  rocks  near  Carlton  peak  and  along  the 
north  shore  of  Lake  Superior.  They  are  small  black  tufted 
plants  distinguished  from  all  other  mosses  by  the  longitudinal 
splitting  of  the  capsular  plant  by  four  lateral  slits  which  do  not 
meet  either  at  the  top  or  bottom  of  the  capsule.  When  dry  the 
capsule  seems  to  shorten  and  the  slits  are  thus  opened  so  that 
spores  may  sift  out  at  the  sides.  The  valves  of  such  capsules 
are  somewhat  sensitive  to  moisture  and  when  conditions  are 
unfavorable  for  the  distribution  of  spores  the  slits  are  likely  to 
remain  closed. 

In  both  of  the  families  of  mosses  which  have  been  described 
there  is  a  central  column  of  sterile  cells  giving  strength  to  the 
capsule,  and  the  spore-mother-cells  are  developed  in  the  region 
between  the  column  and  the  wall.  In  neither  of  the  families  does 
the  column  run  clear  through  the  capsule,  but  the  spore-mother- 
cell  area  extends  over  its  top  like  a  cup  set  over  a  mould.  Quite 
the  same  general  structure  of  capsule  was  observed  in  the  horned 
liverworts  except  that  in  those  plants  the  growth  of  the  capsule 
was  not  definitely  terminated  but  continued  from  the  base.  In 
peat-  and  in  granite-mosses  the  growth  of  the  capsule  is  termi- 
nated after  a  time  and  it  then  contains  no  more  vegetative  cells 
capable  of  further  division.  Therefore,  the  capsule  of  peat-  and 
of  granite-mosses  may  be  regarded  as  built  on  the  general  plan  of 
a  horned  liverwort  capsule,  except  that  the  power  of  continuous 
development  is  lost.  It  might  be  mentioned  here  for  the  sake  of 
clearness  that  the  club-moss  spore-bearing  plant  is  also  supposed 
to  be  an  improvement  over  the  horned  liverwort  type.  But  in 
club-mosses  and  ferns  a  power  of  continuous  growth  is  retained. 

Higher  mosses.  A  peculiar  little  group  of  mosses,  very 
tiny  and  insignificant  in  appearance,  form  reduced  capsules  in 


Minnesota  Plant  Life.  149 

which  no  central  column  exists.  Mosses  of  this  family  have 
not  yet  been  found  in  Minnesota,  although  they  possibly  ex- 
ist. The  rest  of  the  mosses  belong  to  a  division  sometimes 
called  the  true  mosses,  to  distinguish  them  from  the  peat- 
and  from  the  granite-mosses.  There  is  no  particular  occa- 
sion for  the  use  of  the  term  "true"  since  all  alike  belong  to 
the  general  moss  division  of  the  plant  kingdom.  There  are 
more  than  30  families  of  "true"  mosses — not  all  of  them  rep- 
resented in  the  state — and  of  "true"  moss  species  there  are  prob- 
ably from  four  to  five  hundred  in  Minnesota.  The  simplest 
true  mosses  are  very  small  and  the  first-stage  of  the  sexual  plant 
is  more  conspicuous  than  the  second,  for  the  latter  nearly  always 
occurs  as  almost  microscopic  buds,  each  consisting  of  a  short 
stem,  three  or  four  tiny  leaves  and  a  little  group  of  spermaries 
or  egg-organs  at  the  tip.  In  these  mosses  the  capsule  has  no 
lid  and  opens  irregularly.  Only  a  very  few  varieties  with  such 
capsules  are  known  to  exist  in  Minnesota  and  the  great  majority 
of  mosses  have  capsules  which  open  by  lids  and  may  be  known 
as  lid-mosses.  It  is  impossible  here  to  mention,  even  briefly, 
examples  of  all  the  different  families  of  lid-mosses  to  be  found 
within  the  limits  of  the  state.  In  some  kinds  the  plant-body  is 
erect  and  the  egg-organs  are  produced  terminally  upon  the 
axis.  In  others  the  plant-body  is  not  so  commonly  erect  and 
the  egg-organs  are  produced  near  the  tips  of  the  branches. 
In  general  the  lid-mosses  are  divided  into  two  principal  se- 
ries; those  which  bear  their  capsular  plants  at  the  tips  of  the 
stems,  and  those  which  carry  them  on  the  sides.  Sometimes 
it  requires  a  close  examination  of  the  moss  to  determine  to 
which  of  the  two  series  it  belongs.  A  view  of  the  whole  tuft 
might  lead  one  to  suppose  that  the  capsular-plants  were  ter- 
minal on  the  branches,  but  if  a  single  plant  were  isolated  from  its 
neighbors  and  closely  examined  it  might  be  discovered,  per- 
haps, that  the  capsular  plant  was  developed  laterally. 

White  mosses,  bark-mosses  and  dung-mosses.  Among  the 
many  mosses  which  develop  their  capsular  plants  at  the  ends 
of  the  axes  may  be  mentioned  the  white  mosses — grayish  green 
varieties  that  produce  in  the  northern  forest  regions  tufts  the 
size  of  one's  head.  In  these  plants  the  leaves  have  very  much 
the  same  structure  as  peat-moss  leaves,  hence  the  grayish  green 
color  of  the  tufts.  Related  to  such  varieties  are  many  of  the 


Minnesota  Plant  Life. 

bark-mosses  which  attach  themselves  to  the  bark  of  trees,  es- 
pecially near  the  base  of  the  trunk.  In  this  series,  too,  occurs 
a  kind  of  moss  remarkable  for  stationing  itself  upon  the  excre- 
ment of  animals  and  deriving  part  of  its  nourishment  from  or- 
ganic substances.  There  are  no  mosses  which  are  parasites 
upon  other  plants,  or  which  absorb  their  food-materials  ready- 
made,  as  do  the  fungi;  but  the  dung-moss  seems  to  be  develop- 
ing in  that  direction  and  its  descendants  within  the  next  few 
hundred  years  may  find  themselves  within  the  category  of  de- 
pendent plants. 

Turf-mosses,  rose-mosses  and  cup-mosses.  Another  group 
of  mosses  which  belongs  to  the  first  series  may  be  termed  the 
turf-mosses  from  their  prevalence  in  damp  lawns,  especially  near 
the  foundation  of  houses  and  around  verandas.  They  evidently 
select  regions  a  little  more  moist  than  the  lawn-grass  prefers. 
When  they  fruit  they  form  somewhat  pear-shaped  capsules  with 
large  central  columns  of  sterile  tissue.  Here,  too,  are  the  rose- 
mosses  which  produce  what  are  called,  for  lack  of  a  better  term, 
"moss-flowers."  Mosses  of  this  sort  growing  in  clusters  in 
some  shaded  ravine  or  upon  moist  logs  in  the  forest  resemble 
clusters  of  little  green  roses  a  quarter  of  an  inch  or  so  in  diam- 
eter. At  the  end  of  each  short  erect  stem  a  rose-like  cluster  of 
leaves  is  produced  and  at  the  centre  of  each  cluster  the  egg- 
organs  or  spermaries  are  developed  in  little  clumps.  Related 
to  them  are  the  small  stolon-bearing  mosses  \vhich  under  some 
conditions  are  erect-bodied  plants,  but  when  about  to  propagate 
have  the  power  of  pushing  out  prostrate,  runner-like,  leafy  stems. 
These  become  rooted  at  the  tips  and  thus  enable  the  plant  to 
widen  its  circle  of  growth. 

Among  the  mosses  of  this  general  series  there  are  some  forms 
which  produce  gemmae  a  very  little  after  the  fashion  of  the 
umbrella-liverwort.  In  one  variety,  which  may  be  called  the 
gemma-cup-moss,  cup-shaped  groups  of  leaves  at  the  end  of  a 
stem  inclose  a  growth  of  tiny  stalked  gemmae.  When  the 
gemmae  fall  off  they  send  forth  alga-like  threads  of  the  first- 
stage  and  upon  these  threads  buds  may  develop  carrying  the 
plant  over  into  its  second-stage.  In  other  kinds  the  gemmae  are 
produced  upon  the  leaves,  forming  little  clusters  generally  to- 
ward the  tip  of  the  leaf  that  bears  them.  In  mosses,  the  gem- 


Minnesota  Plant  Life. 


151 


niae  cannot  be  viewed  as  they  were  in  the  gemma-liverwort,  as 
little  modified,  specialized  branches  of  the  general  plant-body, 
but  they  must  rather  be  considered  to  belong  to  the  first-stage. 
When  they  are  produced  upon  a  leaf  or  at  the  end  of  a  stem, 
the  best  explanation  seems  to  be  this:  The  first-stage  of  the 
moss-plant  is  the  most  fundamental  and  is  the  original  state  of 
the  plant.  The  second-stage — what  is  called  the  "moss-plant" 
—is  a  more  or  less  highly  organized  reproductive  branch.  Then 
any  cell  of  the  second-stage  about  to  develop  as  a  propagative 
body  would  naturally  grow  out  into  the  filaments  of  the  first- 
stage  ;  and  this  actually  takes  place  when  moss  leaves  or  bits  of 
stem  are  separated  from  the  rest  of  their  body.  But  when 
gemmae  are  produced  it  would  seem  that  these  filaments,  grow- 
ing out  from  the  ordinary  cells  of  the  plant-body,  have  gained 
the  power  of  forming  small,  massive,  bulging  tubers  in  which 
more  nutriment  can  be  stored  than  in  the  ordinary  slender  fila- 
ments. So  then  the  gemmae,  although  apparently  borne  upon 
the  body  of  the  second-stage,  should  be  considered  as  really  be- 
longing to  the  first-stage  of  the  moss  sexual  plant. 

Hairy-capped  mosses.  A  number  of  other  forms  must  be 
passed  with  brief  mention.  Among  these  are  the  hairy-capped 
mosses,  remarkable  for  the  peculiar  structure  of  their  leaves, 
for  the  formation  of  capsular  plants  during  the  summer  and  au- 
tumn of  one  year  and  their  maturation  during  the  spring  of  the 
next,  and  for  the  curious  Robinson-Crusoe-like  hoods  that  are 
carried  on  the  tops  of  the  capsular  plants.  They  are  many  of 
them  adapted  to  very  dry  localities  and  are  common  in  pine 
barrens. 

The  second  series  of  lid-mosses  includes  those  forms  in  which 
the  egg-organs  are  developed  near  the  axils  of  leaves  rather  than 
terminally  upon  the  stems. 

River-mosses.  Here  are  the  river-mosses,  characterized  by 
their  three-ranked  arrangement  of  leaves  without  midribs  and 
the  short  stems  of  the  capsular  plants.  Since  the  capsules  are 
formed  below  the  surface  of  the  water  there  is  no  necessity  of 
their  being  borne  on  long  slender  stems.  The  object  of  the 
slender  stem  is  to  aid  in  wind-dissemination  of  spores  and  ob- 
viously, then,  short  stems  might  be  expected  to  support  the 
submerged  capsules. 


152  Minnesota  Plant  Life. 

Arbor-vitae  mosses.  The  arbor-vitae  moss,  developing  pros- 
trate branches  of  a  peculiar  fern-leaf  aspect  and  growing  in 
moist  woods,  furnishes  another  example  in  which  the  egg-organs 
are  not  terminal  on  the  stem.  The  branch  systems  of  this  moss 
are  exceedingly  beautiful  objects.  They  consist  of  central 
stems  with  lateral  rows  of  shorter  branches  diminishing  towards 
the  apex  of  the  main  axis,  so  that  the  whole  branch-system  looks 
like  a  small  green  fern-leaf  or  feather.  Sometimes  three  or  four 
of  such  feather-like  branches  are  produced  in  a  series,  one  at- 
tached to  another.  Such  a  structure  illustrates  the  develop- 
ment of  branches  of  different  orders  in  the  same  plant-body. 
The  axial  branches  may  themselves  bear  other  axial  branches 
and  these  latter  may  bear  the  subordinated  short  branches. 

Tree-like  mosses.  In  the  tree-like  moss  which  is  found 
growing  near  decaying  logs  in  the  forest  or  on  dark  wooded 
banks,  the  axial  branch  stands  erect  like  a  little  tree-trunk  on 
different  sides  of  which  are  arranged  the  subordinated  branches 
so  that  the  whole  aspect  of  the  plant  is  very  much  like  that  of 
a  miniature  palm-tree  two  or  three  inches  high.  These  tree- 
like mosses  have  also  another  sort  of  stem  which  runs  along  the 
ground — a  kind  of  rootstock  from  which  the  erect  stems  spring. 
The  leaves  upon  the  trunk  of  the  tree-like  moss  are  brown  scales 
without  leaf-green  and  it  is  only  upon  the  secondary  branches 
—the  short  branches — that  leaves  with  leaf-green  are  abun- 
dantly formed.  In  high-types  of  moss  plant-bodies  a  consid- 
erable differentiation  may  exist  between  the  kinds  of  stems. 
There  may  be  prostrate  creeping  stems,  erect  axial  stems,  di- 
vergent secondary  foliage  stems,  prolonged  stolons  extended 
for  propagative  purposes,  and  special  stems  upon  which  the 
egg-organs  and  spermaries  are  particularly  aggregated. 

Carpet-mosses  and  pool-mosses.  Among  the  mosses  of  this 
highest  division,  the  carpet-mosses  which  cover  the  surfaces  of 
fallen  logs,  peeling  off  regularly  in  carpet-like  masses,  furnish  a 
type  in  which  a  considerable  variety  of  branching  exists.  Some 
plants  of  the  carpet-moss  varieties  are  quite  aquatic  in  their 
habits,  and  are  to  be  sought  not  so  much  in  the  running  wa- 
ter which  the  river-mosses  frequent  as  in  quiet  pools  among 
algae,  in  overflowed  meadows  and  in  lakes. 


Minnesota  Plant  Life. 


153 


Spore-distribution  by  mosses.  Before  closing  the  account 
of  the  mosses  it  will  be  profitable  to  examine  somewhat  more 
fully  the  methods  of  spore-dissemination  which  are  employed 

by  the  high- 
ly developed 
forms,  and 
'  the  carpet- 
mosses  may 

be  chosen  as  examples.  Here  the  plant- 
body  is  variously  branched,  the  branches 
being  interlaced  and  the  whole  spread 
out  in  a  soft  green  turf.  On  some  of  the 
lateral  branches  rising  vertically  into  the 
air  are  borne  the  capsular  plants.  Their 
slender  stalks  are  of  a  reddish-brown  col- 
or and  if  closely  scrutinized  will  be  found 
to  be  twisted  or  fluted.  They  are  an  inch 
or  more  in  length  and  at  the  end,  nodding 
strongly  to  one  side,  is  the  slender  urn- 
shaped  capsule  with  a  distinct  lid.  The 

cells  of  the 
wall  where 
the  lid  joins 
the  urn  are 
peculia  rly 

flat  and  low,  so  that  when  the  proper  con- 
ditions of  moisture  are  at  hand  the  urn 
easily  cuts  off  its  lid  and  on  account  of 
the  inclined  position  of  the  capsule  opens 
its  mouth  towards  the  side.  The  greater 
portion  of  the  mouth  of  the  urn  is  closed 
by  a  plug  consisting  of  the  end  of  the 
central  strengthening  column,  and  only 
a  narrow  circular  slit  between  this  plug 
and  the  wall  is  left  through  which  the 
spores  may  be  sifted  out.  After  the  lid 

has  fallen  two  rows  of  curious,  slender  teeth  are  seen  to  pro- 
ject outside  the  circular  slit  arching  over  it  toward  the  cen- 
tre. These  teeth  are  very  sensitive  to  moisture  and  when 


FIG.  48.  A  moss  leafy-plant, 
with  prostrate  propagative 
branch  and  erect  female 
reproductive  branch.  On 
the  latter  two  egg-organs 
have  developed  their  eggs 
into  capsular  plants,  one 
of  which  is  ejecting  spores. 
The  two  round  bodies  are 
spores  much  magnified. 
After  Atkinson. 


154  Minnesota  Plant  Life. 

the  conditions  are  favorable  for  spore-dissemination  they  separate 
from  each  other  a  little  and  allow  the  spores  to  scatter  out  be- 
tween them.  But  when  the  conditions  are  unfavorable  they  close 
over  the  slit  and  the  spores  are  not  permitted  to  escape.  The 
ring  of  teeth  is  one  portion  of  the  automatic  spore-distribut- 
ing machinery  of  the  capsular  plant  and  the  twist  in  the  stalk 
is  another  device  which  plays  its  part  in  the  perfected  mechan- 
ism. Under  varying  states  of  moisture  the  stalk  slowly  twists 
and  untwists  so  that  the  mouth  of  the  nodding  urn  is  carried 
through  a  circle  dispersing  its  spores  as  it  turns  from  side  to  side. 
Such  an  apparatus  insures  the  dissemination  of  spores  toward 
all  points  of  the  compass  and  the  teeth  at  the  edge  of  the  urn 
may  be  depended  upon  to  retain  the  spores  if  the  conditions 
are  not  suitable  for  their  ejection. 

Such  artifices  as  these,  together  with  the  large  size  of  some 
moss-capsules  and  the  considerable  number  of  spores  which  they 
contain,  mark  an  advance  over  liverwort  mechanisms  and  the 
moss  capsular  fruit,  exceedingly  nice  in  its  adaptations,  is  the 
most  perfect  and  logical  result  of  those  lines  of  development 
which  were  begun  in  the  peat-moss  capsule.  The  failure  of  the 
moss  capsular  plant  to  achieve  the  highest  rank  is  because  of  its 
having  lost  the  valuable  power  of  indeterminate  development 
which  was  possessed  by  its  horned  liverwort  prototype. 

Superiority  of  the  moss-capsule  over  the  liverwort-capsule. 
Another  point  of  difference  between  the  moss  capsular-plant 
and  that  of  the  liverwort,  and  indicating  the  higher  rank  of  the 
former,  lies  in  the  greater  development  of  starch-producing 
areas  in  the  moss.  This  is  why  the  capsules  of  liverworts  are 
generally  black  while  the  capsules  of  mosses  are  generally  green. 
The  liverwort  capsule  is  merely  a  thin  shell  surrounding  the 
spores  and  the  black  color  of  the  whole  body  is  given  equally 
by  the  spores  and  their  wall,  but  the  wall  of  the  moss-capsule 
is  like  a  leaf  in  its  physiology.  It  consists  of  several  layers  of 
cells,  the  outer  portion  of  which  functions  as  skin,  while  under- 
neath there  are  areas  in  which  leaf-green  is  formed.  Thus  the 
moss  capsular  plant  is  not  merely  an  elaboration  of  a  fecundated 
egg  into  a  group  of  spores  enclosed  in  a  protective  membrane, 
but  it  is  in  a  marked  degree  an  independent  organism.  It  is 
quite  independent  so  far  as  its  assimilative  power  goes,  and  if, 


Minnesota  Plant  Life,  155 

instead  of  remaining  perched  upon  the  sexual  plant  at  the  point 
where  its  parental  egg-organ  was  developed,  it  had  the  knack 
of  stepping  off  and  driving  its  own  root-system  into  the  soil  it 
would  be  entirely  independent.  This,  however,  is  exactly  what 
the  ancestral  fern  capsular  plants  are  supposed  to  have  done,  so 
that  the  fern  plant  as  it  grows  in  the  woods  may  be  compared 
properly,  not  to  the  leafy  moss-plant  but  to  a  very  highly  im- 
proved moss  capsular  plant  with  leaves  and  roots  of  its  own. 

A  primitive  attempt  to  develop  a  special  leaf-area  is  seen  in 
the  capsules  of  the  dung-mosses.  In  these  the  region  between 
the  capsule  proper  and  the  stalk  is  flared  out  into  a  green  collar 
and  this  is  essentially  a  starch-making  expansion  of  the  general 
plant  surface.  But  that  is  precisely  what  a  leaf  is  structurally, 
for  it  also  may  be  described  as  normally  a  starch-making  expan- 
sion. It  is  true  a  great  many  leaves  come  in  higher  forms  to  as- 
sume entirely  different  functions,  but  the  appearance  of  the  leaf 
must  be  regarded  as  connected  with  starch-making,  for  orig- 
inally this  was  probably  the  function  of  all  leaves,  however  far 
some  modern  forms  may  have  abandoned  it. 

Had  the  moss  capsular  plants  not  originally  given  up,  in  the 
peat-moss  types,  the  power  of  growing  continuously,  or  if  they 
had  independently  attained  this  power,  there  is  no  reason  why 
they  should  not  have  given  rise  to  many  interesting  and  complex 
higher  forms.  But  no  matter  how  perfect  a  moss  capsular 
plant  may  become,  no  matter  how  skillfully  it  may  distribute  its 
spores,  or  provide  for  the  manufacture  of  starch  by  its  own  leaf- 
green  independent  of  the  parent  sexual  plant,  it  always  comes 
to  a  point  when  it  is  completely  mature,  can  develop  no  farther, 
must  eject  its  spores  and  perish.  For  this  reason  mosses  con- 
stitute what  is  called  a  terminal  type  and  there  are  no  higher 
forms  of  plants  regarded  as  derived  from  them. 


Chapter  XVII. 

Christmas-green  Plants  or  Club-mosses* 


The  plants  known  as  club-mosses  are  the  ones  so  abun- 
dantly used  in  the  manufacture  of  Christmas-green  decorations, 
wreaths  and  festoons.  Their  spores  are  collected  and  sold 
at  the  drug-stores  under  the  name  of  lycopo- 
dium  powder,  since  the  small,  smooth,  oily 
spheres  are  very  difficult  to  moisten  and  are 
useful  to  prevent  chafing.  There  are  about 
twelve  species  in  Minnesota,  of  which  some, 
known  as  the  smaller  club-mosses  or  rock- 
club-mosses,  are  distinguished  by  the  posses- 
sion of  two  sizes  of  spores,  the  significance  of 
which  will  be  considered  later.  All  Minne- 
sota species  of  club-mosses  are  terrestrial, 
growing  particularly  in  the  pine  woods,  and 
they  are  known  also  as  ground-pines.  In  the 
tropics,  however,  and  in  the  southern  hemi- 
sphere there  are  varieties  of  club-mosses  which 
perch  upon  the  branches  of  trees  and  hang  in 
festoons  along  the  trunks. 

Life-history  of  a  club-moss.  The  life-his- 
tory of  the  common  Christmas-green  club- 
moss  is  somewhat  as  follows :  The  spores, 
produced  in  large  quantities,  germinate  near 
the  surface  of  the  ground  and  there  form  di- 
minutive sexual  plants  about  the  size  of  pin- 
heads.  Upon  these  tiny  creatures  the  sperma- 
ries  and  egg-organs  are  produced.  The  sperms 
have  two  swimming-hairs  like  those  of  mosses.  The  gen- 
eral structure  of  the  spermary  and  egg-organ  is  quite  like  that 
in  the  horned  liverwort,  and  the  sexual  plant  of  the  club-moss 
may  be  compared  to  a  horned  liverwort  prostrate  stem  very 


FIG.  49.  Branch  of  a 
club-moss  plant, 
bearing  two  cones; 
with  a  single  leaf  of 
the  cone,  showing 
the  spore  case  and 
one  of  the  spores, 
the  latter  much  mag- 
nified. After  Atkin- 
son. 


Minnesota  Plant  Life. 


157 


much  reduced  in  size.  When  an  egg  lying  at  the  bottom  of  the 
organ  which  produced  it  has  been  fecundated,  it  segments  by 
partition-walls.  One  of  the  first  two  cells  develops  into  the 
embryo.  Some  of  the  cells  later  produced  form  the  first  leaf 
of  the  embryo  plant.  Another  group  forms  the  apex  of  the 
stem,  and  still  another  matures  into  a  bulbous  body  which  nurses 
upon  the  tissues  of  the  sexual  plant ;  while,  much  later,  from  the 
interior  of  a  root-like  elongation  a  group  of  cells  pushes  its  way 
out  as  the  first  true  root. 

In  all  the  higher  plants  roots  seem  to  have  originated  from 
inner  portions  of  the  plant-body  and  may  be  regarded  as  being 
everywhere  protrusions  of  the  sap-conducting  areas,  so  that  the 
root  is  essentially  an  absorbent  tract,  while  its  functions  of  sup- 
port are  secondary. 

The  embryo  plant  thus  started  on  its  career  continues  to 
grow,  thickening  its  stem,  forming  new  leaves  and  branches  and 
multiplying  its  roots.  Unlike  the  moss  capsular  plant,  but  like 
the  capsular  plant  of  the  horned  liverwort,  it  never  of  its  own 
accord  stops  growing,  but  only  when  the  growth  is  terminated 
by  outward  unfavorable  conditions.  As  it  grows  and  branches 
year  by  year,  it  soon  becomes  strong  enough  to  form  spore- 
producing  areas  of  its  own. 

In  club-mosses  the  spores  are  in  little  pouches,  one  on  the 
upper  side  of  each  leaf  on  the  cone-shaped  tip  of  some  branch. 
The  end  of  the  branch  which  produces  spores  becomes  cov- 
ered with  leaves,  sometimes  of  a  different  color,  drier  and  paler 
than  the  ordinary  foliage  leaves.  Such  cones  are  equivalent 
to  the  cones  of  pine-trees  which  are  supposed,  indeed,  to  have 
arisen  from  similar  simple  types.  Each  cone  consists  of  an 
axis  clothed  with  spore-bearing  leaves.  Since  the  latter  in  most 
club-mosses  are  specialized  to  some  extent  for  their  reproduc- 
tive functions,  they  progressively  abandon  the  starch-making 
function ;  hence,  not  needing  illumination,  they  stand  closer  to- 
gether, overlapping  each  other  as  they  would  not  do  if  depend- 
ent upon  the  sunlight  for  leaf-green  energy.  Having  taken 
such  positions  they  become  bleached  and  while  the  general 
plant-body  of  a  club-moss  is  provided  with  green,  unbranched, 
rather  needle-shaped  leaves,  the  cones  by  their  yellow  color  and 
flatter  and  more  closely  crowded  leaves,  become  distinct  areas 
of  the  plant.  Yet  in  types  of  club-mosses  lower  than  the  ordi- 


158 


Minnesota  Plant  Life. 


nary  Christmas-green  variety,  the  same  leaf  which  produces  a 
spore-case  upon  its  upper  surface  is  also  depended  upon  by  the 
plant  for  leaf-green  work,  and  the  division  of  labor  marks  only 
the  higher  types. 

The  lowest  in  structure  of  all  club-mosses  is  a  New  Zealand 
form  not  more  than  an  inch  and  a  half  or  two  inches  in  height 
and  typically  unbranched.  A  single  slender  erect  axis  is  pro- 
duced, bearing  foliage  leaves  near  the  base  in  a  little  rosette,  while 
above,  the  end  of  the  stem  develops  as  a  cone  with  small  spore- 
forming  leaves.  Such  a  plant  may  be  regarded  as  equivalent 
to  the  cylindrical  capsule  of  a 
horned  liverwort  in  which  longi- 
tudinal and  transverse  bands  of 
sterile  cells  have  been  developed 
— something  which  was  foreshad- 
owed in  certain  horned  liver- 
worts— separating  into  chambers 
the  general  layer  of  spore-moth- 
er-cells surrounding  the  central 
column.  It  is  conjectured  that 
the  sterile  tissue  in  the  ancestral 
plants  underneath  each  chamber 
bulged  out  into  a  leaf-like  expan- 
sion and  these  leaves  separated 
from  each  other  longitudinally. 

Therefore    the    axis    Or    Stem    Of    a     FIG- 50.     Flat-branched  club-moss.      After 

Britton  and  Brown. 

club-moss  is  conceived  to  com- 
pare best  with  the  central  cylinder  of  supporting  tissue  in  a 
horned  liverwort  capsule  and  not  with  the  stalk  of  a  moss  cap- 
sule. The  leaves  of  the  cone  are  conceived  to  compare  with 
sections  of  the  capsular  wall,  each  section  bearing  on  its  inner 
surface  its  own  portion  of  the  spore-mother-cell  tract.  The  root 
is  conceived  to  be  a  new  structure,  and  outgrowth  of  the  central 
cylinder.  The  tip  of  the  horned  liverwort  capsule  is  regarded  as 
equivalent  to  the  tip  of  the  cone  in  a  club-moss.  All  these  points 
may  be  best  understood  by  comparison  with  the  simple  New 
Zealand  club-moss  in  which  abundant  branching  of  the  spore- 
producing  plant  does  not  take  place. 

As  the  spore-producing  plant  of  the  club-moss  has  acquired 
new  powers  and  new  perfections  of  structure  along  vegetative 


Minnesota  Plant  Life. 


159 


as  well  as  along  spore-producing  lines,  so  the  sexual  plant — the 
one  developed  from  the  spore — has  become  reduced  and  is  sim- 
pler, smaller  and  less  important  than  the  sexual  plants  of  liver- 
worts or  mosses. 

Different  kinds  of  club-mosses  in  Minnesota.  The  different 
kinds  of  club-mosses  in  Minnesota  are  distinguished  by  differ- 
ent habits  of  branching,  different  shapes  of  leaves  and  the  vary- 
ing distinctness  with  which  the  cone-area  is  blocked  out  in  the 
general  plant-body.  Some,  as  the  tree-like  club-moss  or  ground- 
pine,  have  erect  stems  with  subsidiary  branches  like  those  of  a 

pine.     Another  kind  has  the  leaves 
flattened  in  a  peculiar  way  like  the 
leaves  of  the  white  cedar.     In  still 
another     species     the     plant-body 
branches  loosely  and  trails  over  the 
ground,   while  in  yet  another  the 
stem  forks,  and  tufts 
of  branches  are  pro- 
duced, reminding  one 
a   little   of   the   true- 

FIG.  51.     Smaller  club-moss.     To  the  left  a  plant  with  three     JVIQCCPC 
cones,  next  a  single  cone  dissected  to  show  the  spore 

cases,  next  a  single  large-spore-case  with  four  spores  The     fOCk-Cltlb- 

revealed,  and  on  the  right  a  small-spore-case  with  the  ^^  . . 

small  spores  sifting  out.     After  Atkinson.  mOSSCS.        1  he    Smaller 

club-mosses  or  rock- 
club-mosses  are  pretty  abundant  throughout  the  state  wher- 
ever dry  rocks  or  rocky  hills  occur.  The  leaves  in  the  com- 
mon species  are  pressed  close  together  along  the  stem  and 
each  has  at  the  end  a  white  bristling  hair,  giving  a  hoary  ap- 
pearance to  the  whole  plant.  The  cone-areas  are  not  so  dis- 
tinctly different  in  appearance  from  the  rest  of  the  plant-body 
as  in  the  larger  club-mosses.  The  great  peculiarity  of  these 
plants  is  their  production  of  two  kinds  of  spores.  In  some  of 
their  spore-cases  two  hundred  or  more  small  spores  will  be 
produced,  each  somewhat  pyramid-shaped,  while  in  other  spore- 
cases — perhaps  in  the  very  same  cone — there  will  be  produced 
four  much  larger  spores  with  variously  marked  walls  and  of  a 
generally  spherical  shape.  When  a  smaller  spore  germinates, 
it  produces  a  little  male  plant  so  insignificant  that  it  never  comes 
outside  its  spore-wall,  but  forms  and  matures  altogether  within. 
This  little  male  creature  produces  a  few  sperm  cells.  When 


160  Minnesota  Plant  Life. 

the  spore-wall  breaks,  as  it  does  eventually,  the  sperm-cells  are 
liberated  and  swim  away  in  the  water  after  some  rain  or  heavy 
dew.  When  the  large-spores  germinate  each  produces  a  fe- 
male plant  which,  like  the  male,  remains  within  the  spore  and 
does  not  push  out  as  did  the  sexual  plants  of  liverworts,  mosses 
and  the  larger  club-mosses.  The  female  is  very  much  larger 
than  the  male,  and  each  plant  fills  the  spore  from  which  it  de- 
veloped. When  the  female  is  mature,  one,  or  sometimes  more, 
egg-producing  organs  are  formed  at  the  surface  of  the  cell-mass 
inclosed  in  the  large-spore.  After  the  egg-organ  with  its  in- 
closed egg  has  matured,  the  wall  of  the  large-spore  breaks  just 
over  the  imbedded  neck  of  the  egg-organ.  This  permits  sper- 
matozoids  to  enter  and  by  means  of  one  of  them  the  egg  is 
fecundated  and  begins  segmenting  into  an  embryo  in  which 
stem-areas,  root-areas,  leaf-areas  and  nursing-foot-areas  are  pro- 
duced. In  the  smaller  club-moss  a  great  reduction  of  the  sex- 
ual generation  is  apparent.  The  sexual  plants  do  not  even 
come  outside  of  their  spore-walls.  They  do  no  independent 
vegetative  work  but  the  species  depends  for  its  subsistence  upon 
the  starch-making  power  of  the  spore-producing  plant. 

Origin  of  the  seed  of  higher  plants.  The  smaller  club- 
mosses  while  of  slight  economic  importance  are  of  extraordinary 
scientific  interest  because  they  illustrate  how  in  the  history  of 
the  vegetable  kingdom  that  important  structure,  the  seed  of 
higher  plants,  probably  originated.  The  habit  of  the  female  of 
remaining  within  the  spore  must  have  antedated  the  origin  of 
the  seed.  In  seeds  not  only  does  the  female  remain  within  the 
spore  but  the  spore  remains  within  its  case  and  the  female  ob- 
tains fecundation  of  her  egg  by  the  cooperation  of  a  pollen-tube, 
while  the  spore-case  need  not  open.  When  the  embryo  has 
begun  to  form  from  the  egg  the  whole  spore-case,  with  some 
adjacent  layers  of  cells,  ripens  and  a  seed  is  the  result.  The 
smaller  club-mosses  foreshadow  this  still  more  strongly  in  some 
species  where  the  large-spores  begin  to  germinate  internally  be- 
fore they  fall  from  their  spore-cases.  Yet  no  smaller  club-moss- 
plant  ever  really  produces  a  seed,  for  in  all  of  them  sooner  or 
later  the  spore  is  ejected  from  its  case  and  thus  there  is  pre- 
vented from  arising  the  exact  combination  of  conditions  upon 
which  seed  formation  depends. 


Chapter  XVIII. 


Ferns  and  Water-ferns. 
If 

Related  to  club-mosses  in  about  the  same  manner  that  true 
mosses  are  related  to  horned  liverworts  are  the  ferns,  a  very 
ancient  and  singular  group  of  plants.  In  Minnesota  about  fifty 
species  occur,  found  for  the  most  part  in  woodland.  One  va- 
riety, the  brake,  is  an  exceedingly  common  plant  in  all  burned 
districts  of  the  forest  region. 

Adder's-tongues  and  moonworts.  There  are  two  principal 
groups  of  ferns  recognized  by  botanists.  Of  the  lower  group, 
the  so-called  grape-ferns  or  moonworts  and  the  adder's-tongue 
ferns  are  specimens.  In  these  each  leaf  consists  of  two  lobes, 
one — the  so  called  sterile  lobe — being  devoted  entirely  to 
starch-making,  the  other — the  so  called  fertile  lobe — having  for 
its  exclusive  function  the  production  of  spore-cases.  The  fer- 
tile lobe  grows  from  the  inner  face  of  the  sterile  lobe,  occupy- 
ing relatively  to  the  sterile  lobe  the  same  position  maintained  by 
the  spore-case  of  a  club-moss  with  reference  to  the  leaf  upon 
which  it  was  situated.  It  is  believed  that  the  fertile  lobe  of  an 
adder's-tongue  fern-leaf  is  equivalent  to  a  large,  chambered  and 
overgrown  spore-case  as  displayed  in  the  club-mosses,  and  it  is 
believed  that  the  sterile  segment  of  the  leaf  is  equivalent  to  the 
blade  of  the  spore-case-bearing  leaf  in  the  club-mosses. 

The  adder's-tongue  ferns  with  their  slender  fertile  lobes  bear- 
ing two  rows  of  spore-cases  and  their  undivided  sterile  seg- 
ments, are  simpler  than  the  grape-ferns  with  their  palmately 
branched  leaf-segments.  In  these  plants  the  spores  upon  germ- 
ination give  rise  to  little  tuberous  sexual  plants  which  lie  almost 
imbedded  in  the  soil  and  are  devoid  of  leaf-green,  being  humus 
plants.  Upon  such  little  tubers  the  egg-organs  and  spermaries 
develop  and  after  fecundation  the  egg  forms  an  embryo  which 
nurses  for  a  time  upon  the  sexual  plant,  then  thrusts  its  own 


12 


162 


Minnesota  Plant  Life. 


FlG.  52.     Adder's-tongue  fern.     After  E.  N.  Williams  in  Mediates  Monthly. 


Minnesota  Plant  Life. 


163 


roots  into  the  soil  and  begins  an  independent  life.  The  spore- 
producing  plants  like  those  of  club-mosses  are  perennial,  but 
the  egg-  and  sperm-producing  plants  die  within  a  few  weeks  or 
months  after  they  are  formed. 

Quillworts.  A  very  curious  group  of  plants  known  as  quill- 
worts,  found  growing  on  lake  bottoms  in  northern  Minnesota, 
are  considered  to  be  distant  relatives  of  the  adder's-tongue  ferns. 
They  produce  two  sizes  of  spores,  large  and  small,  and  quite  as 
in  the  life-history  of  the  smaller  club-mosses  the  large-spores 
give  rise  to  internally  developed  females,  while  the  small-spores 
produce  diminutive  males 
not  protruded  beyond  the 
spore  walls.  K  ni  b  r  y  o 
quillwort  plants  originate 
from  the  fecundated  eggs 
and  when  they  have  be- 
come old  enough  renew 
the  production  of  spores. 
These  are  formed  in  cu- 
riously partitioned  cham- 
bers at  the  base  of,  and  on 
the  inner  face  of  the  long 
quill-shaped  leaves.  The 
spore-producing  area  of 
the  leaf  occupies  the  same 
relative  position  with  ref- 
erence to  the  starch-mak- 
ing area  that  was  seen  in 
club-mosses  and  adder's- 
tongue  ferns.  The  upper  portions  of  the  leaves  contain  air- 
chambers  by  means  of  which  the  leaves  stand  erect  at  the  bot- 
tom of  the  lake.  Some  varieties  of  quillworts,  also  represented 
in  Minnesota,  grow  in  swamps  and  marshes  and  cannot  be  dis- 
tinguished except  by  the  closest  observation  from  tufts  of  sedge 
or  grass. 

Ordinary  ferns.  Quite  different  in  a  number  of  structural 
details  are  the  "true"  ferns,  the  group  to  which  almost  nine- 
tenths  of  the  Minnesota  species  belong.  These  are  plants  with 
habits  of  growth  which  are,  in  a  general  way,  pretty  well  known 


FIG.  53.     Virginia  grape-fern.     After  Brittoti  and 
Brown. 


1 64 


Minnesota  Plant  Life. 


by  all  who  frequent  the  woods.  Of  true  ferns  there  are  nine 
families,  only  four  of  which  are  represented  in  Minnesota. 
The  filmy  ferns,  the  tree-ferns,  the  forking  ferns,  the  twining 
ferns  and  the  Borneo  ferns  are  not  represented  by  plants  in- 
digenous to  the  state.  The  families  present  are  the  bracken- 
ferns  and  their  various  allies,  the  flowering  ferns,  the  floating- 
ferns  and  the  four-leaved  water- 
ferns.  Of  these  the  lowest  in  type 
are  the  flowering  ferns,  three  spe- 
cies of  which  occur  in  Minnesota. 
One  of  them,  known  as  the  inter- 
rupted fern,  is  a  common  plant, 
presenting  a  peculiar  appearance  as 
if  somewhere  near  the  middle  of  the 
large  leaf  two  or  three  leaflets  had 
shriveled.  These  leaflets,  unlike 


Fie*.  54.     A  quillwort  plant.     After  At- 
kinson. 


FIG.  55.     Clayton's  or  interrupted  fern.     After 
Hritton  and  Brown. 


the  rest,  have  a  brown  and  withered  look.  If  examined  closely 
it  will  be  discovered  that  this  is  due  to  their  being  covered  with 
spore-cases  of  a  brown  color,  while  the  rest  of  the  leaflets  pro- 
duce no  spore-cases  whatever.  Another  fern  of  this  family  is 
the  cinnamon  fern  which  forms  leaves  of  two  sorts,  some 


Minnesota  Plant  Life. 


'65 


much  larger  and  green,  adapted  solely  to  starch-making,  others 
smaller,  of  a  cinnamon  color  and  devoted  particularly  to  spore- 
making.  A  third  species  is  sometimes  known  as  the  royal  fern. 
The  leaves  are  compoundly  branched  and  leaflets  towards  the 
tip  produce  spore-cases,  while  lower  branches  of  the  leaf  make 
leaf-green  and  form  no  spores. 

Of  the  common  ferns  belonging  to  the  family  of  bracken- 
ferns,    there   are    the   polypody,    abundant   upon    rocks   in    all 


FIG.  56.     Bed    of    ferns.     Sensitive    fern    in  middle    of    foreground.     After    photograph    by 

Williams. 

parts  of  the  state;  the  maiden-hair,  with  its  slender,  wire-like 
leaf-stems  and  graceful  leaflets,  common  in  woodlands;  the 
bracken-fern  with  its  loosely  branched  leaves;  the  cliff-brakes 
growing  in  crevices  on  cliffs  and  high  banks;  the  spleen- 
worts  and  lady-ferns  with  their  delicate  leaves;  the  walking 
ferns  found  upon  rocks  and  so  named  from  their  habit  of 
stretching  out  their  long  leaves  and  driving  the  tips  into  the 
ground  forming  there  buds  from  which  new  plants  develop; 


1 66 


Minnesota  Plant  Life. 


the  beech-ferns;  the  shield-ferns,  and  the  bulblet-ferns  recog- 
nized by  the  formation  on  their  leaves  of  bulbils  which  drop 
off  and  propagate  the  plant.  Besides  these  there  are  the  little 
brown  Woodsias  found  upon  rocks  and  distinguished  by  the 
dry  aspect  of  their  leaves,  and,  in  rich  woods,  the  sensitive 
ferns  and  ostrich-ferns  peculiar  among  bracken-ferns  for  the 
development  of  two  kinds  of  leaves  much  as  in  the  flower- 
ing ferns.  The  ostrich-fern  especially  is  a  regal  plant.  Grow- 
ing in  damp  glades  of 
the  forest  it  spreads  its 
tall  graceful  fronds,  out- 
lining a  green  Corinthian 
capital.  In  the  centre 
there  spring  up  four  or 
five  smaller  feather- 
shaped  brown  leaves 
which  have  abandoned 
starch-making  and  devote 
themselves  entirely  to  the 
production  of  spores. 

The  four-leaved  water- 
fern.  Most  remarkable 
in  some  respects  of  all 
ferns  is  the  four-leaved 
water-fern.  It  does  not 
always  grow  in  water  but 
is  found  in  dry  creek- 
beds  at  the  extreme  western  edge  of  Minnesota.  The  plant- 
body  consists  of  a  thread-like,  creeping,  branched  stem  from 
which  small  leaves,  resembling  four-leaved  clovers,  arise.  These 
are  the  vegetative  leaves  of  the  plant,  but  the  spore-producing 
leaves  are  modified  into  capsules  about  the  shape  of  an  ordinary 
bean  but  considerably  smaller.  If  one  of  these  beans  is  chipped 
on  the  side  and  placed  in  a  dish  of  water  it  will  open  like  a  clam- 
shell and  in  about  twenty  minutes  a  centipede-like  object,  three 
or  four  inches  long  and  as  thick  as  a  crochet  needle  will  uncoil 
itself.  It  seems  absolutely  impossible  that  so  large  an  object 
could  have  been  packed  away  inside  the  bean-like  leaf.  The 


FIG.  57.     Cliff-brake.     After  Britton  and  Brown. 


Minnesota  Plant  Life. 


backbone  of  the  centipede-shaped  affair  has,  however,  the  ap- 
pearance of  clear  jelly  and  is  enormously  swollen  by  the  ab- 
sorption of  water.  The  "legs"  of  the  centipede,  twelve  to 
eighteen  in  number  on  each  side,  are  yellowish  and  upon  close 
examination  appear  to  be  elongated  transparent  sacs  in  each 
of  which  a  number  of  pearly  yellow  bodies  of  generally  oval 


!•'!<;.   58.     The   interrupted  fern   (in   background)  and  shield-ferns   (in   foreground).     After 
photograph  by  Williams. 

shape  are  situated.  These  bodies  are  spore-cases,  some  of 
them  containing  sixty  four  small-spores  and  others  containing 
one  large-spore,  each.  As*  in  quillworts  and  smaller  club- 
mosses,  the  small-spores  produce  little  reduced  males  while  the 
large -spores  develop  females.  The  egg  of  the  female,  never 
more  than  one  to  the  plant,  segments,  after  fecundation,  into 


1 68 


Minnesota  Plant  Life, 


Four-leaved  water-fern. 
Brown. 


After   Britton   and 


an  embryo  which  sucks 
up  all  the  surplus  food- 
materials  that  were  de- 
posited  in  the  large- 
spore,  produces  a  root  of 
its  own,  thrusts  it  into  the 
soil  or  water  and  begins 
an  independent  existence. 
The  Minnesota  variety  is 
a  land-dwelling  species  of 
a  group  which  is  more 
generally  aquatic,  hence 
the  name  of  water-fern. 

The  fusion  of  the  egg 
and  the  sperm  in  ferns  can 
take  place  only  after  heavy 
rains,  or  when  the  melt- 
ing snows  of  early  springs  FlG- 
have  flooded  the  station 
of  the  plant.    All  ferns,  and  indeed,  most  plants,  up  to  and  includ- 
ing the  cycad-palms  and  ginkgo  trees,  are  essentially  aquatic  in 

their  breeding  hab- 
its. Most  of  them 
have  motile  sperms 
provided  with  swim- 
ming hairs,  and  un- 
less there  is  a  me- 
dium in  which  the 
sperm  can  swim  it 
will  never  reach  the 

egg- 

Floating  ferns. 

The  family  of  the 
floating  ferns  is  rep- 
resented in  Minne- 
sota by  a  little  plant 
called  A  zolla,  not  un- 

FIG.  60.     A  sexual  fern-plant  somewhat  magnified.     Its  nat-  COmmon      m     greeil- 

ural  size  is  about  a  quarter  of  an  inch  across.     The  round  h  O  U  S  C  S      where     it 

bodies  are  spermaries,  the  chimney-shaped  ones  are  egg-  ,, 

organs,  seen  from  below.     After  Atkinson.  floats    UpOll    the    SU1~- 


Minnesota  Plant  Life. 


169 


face  of  the  water  in  tanks.  It  has  a  much  branched  stem  and 
tiny,  rather  ovate  leaves.  The  whole  body  resembles  that  of  a 
scale-moss.  As  they  grow  the  leaves  form  peculiar  cavities, 
opening  by  a  narrow  aperture  through  which  a  little  alga  in- 
serts itself  and  is  a  constant  companion  of  the  Azolla  plant,  for 
in  all  Azolla  leaves  are  found  growths  of  this  little  blue-green 
alga.  Like  the  leaves  of  the  scale-mosses,  those  of  Azolla  have 
two  lobes,  one,  the  floating  lobe,  lying  upon  the  surface  of  the 
water  and  the  other,  the  submerged  lobe,  lying  below.  The 
spore-cases  are  borne  in  groups  upon  the  submerged  lobe. 


FIG.  61.  A  fern-plant  embryo  imbedded  in  the  enlarged  egg-organ,  where  it  arose  by  seg- 
mentation of  an  egg.  S,  tip  of  rudimentary  stem;  I,,  tip  of  first  leaf;  R,  tip  of  primitive 
rootlet;  F,  nursing  foot.  Much  magnified.  After  Atkinson. 

There  are  twro  kinds  of  spores,  large  and  small,  and  several  of 
the  spore-cases  which  produce  small-spores  are  developed  in 
clusters  and  inclosed  by  a  general  protective  wall.  The  spore- 
cases  which  develop  the  large-spores  occur  singly  within  such 
a  wall  and  each  large-spore-case  produces  a  single  large-spore. 
When  the  small-spore-cases  open,  simultaneously  several  small- 
spores  escape  imbedded  in  a  lump  of  frothy  mucilage  upon 
which  curious  little  anchor-shaped  barbed  hairs  are  disposed. 
The  large-spore,  when  its  case  opens,  is  found  to  have  one  end  of 
its  wall  provided  with  low  flat-topped  excrescences  from  each 


Minnesota  Plant  Life. 


of  which  a  tuft  of  delicate  threads  protrudes.  As  the  frothy 
masses  in  which  the  small-spores  are  imbedded  drift  near  one 
of  the  large-spores, 
their  anchors  be- 
come entangled  i  n 
the  hairs  of  the  large- 
spore,  and  thus  one 
or  more  of  the  mass- 
es is  secured  in  such 
a  position  that  when 
the  small-spores 
germinate,  protrud- 
ing from  each  a 

little     tubular     Olailt-     ^IG-  62.     Portion  of  maiden-hair  fern-leaf,  showing  marginal 

pockets,  which  serve  to  protect  the  clusters  of  spore -cases 
bOCly,       the       SpermS,  under  each  flap.     After  Atkinson. 

formed  by  the  male, 

will  not  have  far  to  swim  to  reach  the  egg. 

Explanation  of  what  fern 
leaves  really  are.  In  all  the 
ferns  belonging  to  the  series 
known  as  the  true  ferns,  the 
spore-cases  are  little  stalked  pods 
containing  from  one  to  about 
sixty  four  spores,  never  much  ex- 
ceeding that  number.  These 
spore-cases  may  be  seen  in  the 
polypody,  forming  on  the  under 
side  of  the  leaves  small  brown 
circular  patches.  In  the  maiden- 
hair and  bracken-ferns  they  oc- 
cur under  pocket-shaped  flaps  of 
the  leaf-margin.  In  the  shield- 
ferns  each  group  of  spore-cases 
on  the  under  side  of  the  leaf  is 
protected,  at  least  while  young, 
by  a  shield-shaped  or  umbrella- 
shaped  membrane  growing  over 
the  group.  It  is  the  rule  among 

the  true  ferns  that  the  leaf  which  bears  the  spore-cases  also 

serves  as  the  starch-making  organ  of  the  plant,  but  in  the  OS- 


FIG.  63.  A  patch  of  spore-cases  on  the  back 
of  a  common  polypody-fern-leaf.  Mag- 
nified. After  Atkinson. 


Minnesota  Plant  Life. 


171 


trich-ferns,  the  sensitive  fern,  one  of  the  flowering  ferns,  the 
four-leaved  water-fern  and  some  other  forms  which  have  not 
been  mentioned,  there  is  a  division  of  labor  and  the  leaf  which 
makes  starch  is  not  also  designed  to  produce  spores. 

In  comparing  the  true  ferns  with  the  adder's-tongue  ferns, 
it  would  appear  that  the  condition  of  things  is  somewhat  pe- 
culiar. Since  it  bears  the  spore-cases  it  would  seem  that  the 


cr^ 


^ 


~-    rs^^j&^U  Xs. 

p:a" "  JT^X^  •%     ^ 

o^o^^T^^^SS  ^>S 
s^s^WAte^1:  /  -'-  ~^  -N^  °*> 

-•*•   - .-  *-N\  \  N  i,  \^ 


!•'!<'•.  »>4.  Spore-cases  of  the  common  fern,  much  magnified,  showing  how  the  spring  back 
reverts  and  then  snaps  shut  again,  throwing  the  spores  as  from  a  sling.  After  Atkin- 
son. 

ordinary  fern-leaf  compares  only  with  the  fertile  lobe  of  the 
adder's-tongue  fern-leaf.  This  fertile  lobe  has  greatly  enlarged 
and  assumed  the  function  of  starch-making.  At  the  same  time 
the  spore-cases  have  come  to  be  developed  from  special  cells  at 
its  surface,  not  from  mounds  of  cells  as  in  the  lower  form. 
\Yhat,  now,  has  become  of  the  sterile  segment  of  the  adder's- 
tongue  fern-leaf?  The  most  reasonable  reply  to  this  question 
that  can  be  offered  is  that  it  has  undergone  steady  reduction  and 


172 


Minnesota  Plant  Life. 


FIG.  65.     A  walking-fern  climbing  down  a  hillside.     Buds  form  at  the  very  tips  of  the  slender 
leaves  and  grow  into  new  plants.     After  Atkinson. 


Minnesota  Plant  Life. 


173 


has  finally  disappeared.  In  a  family  of  tropical  ferns  not  rep- 
resented in  Minnesota  are  found  traces  of  this  sterile  segment 
as  stipular  plates  at  the  bases  of  the  leaves.  Therefore,  we  arrive 
at  the  interesting  and  remarkable  hypothesis  that  the  entire 
fern-leaf  compares  with  a  much  elaborated  and  improved  club- 
moss  spore-case.  It  will  be  remembered  that  the  fertile  seg- 
ment of  the  adder's-tongue  leaf  was  believed  to  be  an  over- 
grown chambered  spore-case  arising  from  some  club-moss-like 


FIG.  6(3.     Maiden-hair  ferns  and  lady  ferns.     After  photograph  by  Williams. 

ancestral  condition.  Therefore,  among  true  ferns  the  common 
type  of  leaf  in  which  both  starch-making  and  spore-production 
are  combined,  is  the  primitive  one.  By  a  division  of  labor, 
some  leaves  quite  abandoned  the  habit  of  producing  spore-cases 
and  others  in  the  same  plant  intermitted  the  production  of  leaf- 
green.  Thus  are  explained  the  two  sorts  of  leaf  in  the  ostrich- 
fern  and  the  same  explanation  serves  for  the  cinnamon  fern  and 
its  allies  and  for  the  four-leaved  water  fern. 


174  Minnesota  Plant  Life. 

In  a  word,  the  most  distinctive  feature  of  the  ferns  is  this: 
They  loosened  that  cone-arrangement  of  leaves  which  had  arisen 
in  the  club-mosses  and  greatly  developed  the  spore-case-area 
of  each  leaf  until  such  an  area  became  itself  a  leaf-like  structure, 
while  the  original  blade  of  the  leaf  deteriorated  and  disappeared. 
The  pine  trees,  also  related  to  the  club-mosses,  pursued  a  very 
different  course  of  development  and  retained  the  cone  as  a  struc- 
tural unit.  From  bodies  somewhat  similar  to  pine-cones  it 
is  probable  that  the  flowers  of  all  higher  plants  arose.  The 
club-mosses  then  have  originated  two  great  lines  of  improve- 
ment, one  in  which  the  cone  was  abandoned  as  a  structural  fea- 
ture, giving  rise  to  the  ferns,  the  other,  in  which  the  cone  was 
retained  as  a  structural  feature,  leading  to  the  flozvering  plants. 


Chapter  XIX. 

Scouring-rushes  and  Horse-tails. 


The  peculiar  family  of  plants  known  as  scouring-rushes  or 
horse-tails  was  very  much  better  developed  during  the  age  when 
coal  was  being  deposited  than  it  is  to-day.  Most  of  its  species 
are  extinct,  but  there  remain,  widely  distributed  over  the  world, 
some  forty  different  varieties,  of  which  ten  occur  in  Minnesota. 
They  are  not  very  closely  related  either  to  the  ferns  or  to  the 
club-mosses,  although  they  clearly  belong  in  their  general  vicin- 
ity. The  unbranched  forms  are  known  as  scouring-rushes  on 
account  of  the  usual  deposit  of  silica  in  their  outer  layers. 
This  mineral  is  useful  for  scouring  tinware,  and  rushes  are 
actually  thus  employed  by  some  housewives  in  the  country. 
The  branched  forms  are  known  as  horse-tails  from  their  peculiar 
aspect  as  they  stand  in  fields,  in  the  woods  or  along  the  road- 
side or  railway  tracks. 

Each  variety  of  scouring-rush  or  horse-tail  is  distinguished 
by  an  underground  rootstock  which  shows  much  the  same  struc- 
ture as  the  above-ground  portions.  Sometimes  on  the  root- 
stocks  tuber-like  propagative  swellings  are  formed.  Both  the 
erect  and  subterranean  branches  are  divided  into  very  distinct 
joints  which  may  be  separated  from  each  other  like  sections  of 
stove-pipe,  hence  the  plants  are  also  called  joint-rushes.  In 
some  species  the  plant  produces  only  one  kind  of  erect  stem 
and  at  the  tip  of  this,  or  more  rarely  at  the  tips  of  lateral 
branches,  firm  and  solid  cones  are  borne,  each  made  up  of  little 
shield-shaped  leaves  with  central  stalks.  The  leaves  are  ar- 
ranged in  circles  about  the  axis,  not  in  spirals  as  in  the  cones 
of  club-mosses.  On  the  under  side  of  each  of  the  shield-shaped 
leaves  a  ring  of  spore-cases  is  developed,  commonly  about  eight 
in  a  group.  The  cones  bear  the  leaves  so  close  together  that 
from  their  mutual  pressure  they  assume  a  more  or  less  hexagonal 
outline. 


176  Minnesota  Plant  Life. 

Scouring-rushes  with  two  sorts  of  erect  stems.  In  a  few 
of  the  species  there  are  formed  two  kinds  of  erect  stems.  One 
is  pale  or  reddish  in  color,  softer  to  the  touch,  provided  with 
longer  leaves  below  the  cone,  devoid  of  leaf-green  and  de- 
voted to  the  work  of  spore-production.  The  other  is  repeat- 
edly branched,  the  branches  arising  in  circles  at  the  top  of 
each  joint  of  the  stem.  Upon  such  erect  stems  no  cones 
are  ordinarily  displayed,  but  the  whole  plant-body  is 
green  and  starch-producing.  Both  kinds  of  erect 
branches  are,  however,  very  similar  in  internal  struc- 
ture. They  are  hollow  and  their  wood-threads  are  ar- 
ranged in  a  circle,  usually  with  air-canals  between  them 
and  within  them.  At  the  top  of  each  joint  a  group  of 
leaves  arises  in  a  ring.  These  are  not  used  for  starch- 
making  but  are  reduced  and  scale-like  and  commonly 
blended  together  by  their  edges  into  a  collar  closely 
enveloping  the  lower  part  of  the  joint  immediately 
above.  On  the  special  spore-producing  branches  the 
leaves  are  often  larger  and  less  completely  fused  to- 
gether. Sometimes  the  leaves  are  black  in  color  with 
gray  tips,  as  in  a  well-known  joint  rush  of  Minne- 
sota. In  all  the  varieties  the  starch-making  is  done 
not  by  the  leaves  but  by  the  branch-system,  so  that  in 
this  respect  the  plants  resemble  the  well-known  aspar- 
agus, to  which  they  bear,  however,  no  close  botanical 
relation. 

When  the  spore-cases  on  the  shield-shaped    leaves 
open  to  eject  their  spores,  the  spores  may  be  shaken  out 
into  the  hand  as  a  green  dust.     If  one  watches  this  dust 
as  it  lies  upon  the  hand  immediately  after 

JIG.  67.    A  fruiting  stem 

of  the  horse-taii.  having  been  shaken  from  the  cone,  it  will  be 
s™ere-£aertagtTeds  seen  that  within  a  couple  of  seconds  after  its 
are  aggregated  in  a  deposit  it  fluffs  and  becomes  of  3.  lighter 

cone.      After  Atkin-  .  . 

son.  color.     By  warming  it  gently  with  the  breath 

it  regains  its  darker  hue  and  more  solid  ap- 
pearance, but  in  a  couple  of  seconds  it  fluffs  again  as  it  did 
before.  This  remarkable  behavior  is  explained  if  the  spores  be 
examined  under  a  good  microscope.  It  will  then  be  observed 
that  apparently  attached  to  each  of  them  are  four  delicate  spoon- 


Minnesota  Plant  Life.  177 

shaped  appendages  which  are  very  sensitive  to  moisture.  These, 
when  dampened,  contract  around  the  green  spherical  spores, 
hugging  them  tightly,  but  as  they  dry  they  straighten,  loosen- 
ing the  spore-mass  in  the  process.  This  is  why  the  moistened 
dust  seems  more  solid  than  the  same  dust  when  dry.  The 
spoon-shaped  appendages  originate  by  the  splitting  of  the 
outer  wall  of  the  spore  into  two  ribbons,  as  if  a  couple  of  peel- 
ings had  been  removed.  An  idea  of  the  arrangement  can  be 
obtained  by  imagining  the  cover  of  a  base-ball  unsewed  and  laid 
back.  The  two  pieces  of  cover  would  then  occupy  much  the 
same  position  with  reference  to  the  ball  as  do  the  four  longer 
and  slenderer  spoon-shaped  appendages  with  reference  to  the 
spore. 

Germination  of  spores.  Although  all  the  spores  are  of  the 
same  size  and  appearance,  yet  it  is  the  nature  of  some  of  them 
upon  germina- 
tion to  develop 
little  green, 
prostrate 
male  s,  some- 

tlllllP'  like  Small  FIG.  68.  Scouring-rush  spores;  to  the  left  a  spore  with  appendages 
i  1  i  •  curled  up,  in  moist  air;  to  the  right  a  spore  with  appendages  ex- 

n  O  r  11  6  Q      liver-  tended,  in  dry  air.     After  Atkinson. 

wort  plants, 

while  others  develop  females,  slightly  larger  than  the  males  but 
in  general  closely  resembling  them.  Both  the  male  and  the  fe- 
male scouring-rush  plants  are  provided  with  leaf-green,  emerge 
from  the  spores,  strike  their  root-hairs  into  the  soil  and  lead 
an  independent  existence.  The  males  produce  microscopic 
spherical  spermaries  in  which  arise  spermatozoids  with  large 
numbers  of  swimming  threads.  The  females  produce  a  few 
egg-organs  of  the  characteristic  bottle-shape,  at  the  bottom  of 
each  of  which  a  single  egg  is  formed.  After  the  fecundation  of 
the  egg  during  rains,  or  when  in  some  other  way  plenty  of 
water  is  available  as  a  medium  for  the  locomotion  of  the  sperms, 
the  embryo  of  the  scouring-rush  begins  to  grow  very  much 
as  did  that  of  the  fern.  An  erect  stem  is  first  produced,  then 
from  its  base  a  rootstock.  If  at  the  end  of  the  year  the  erect 
stem  dies,  buds  on  the  rootstock  remain  to  form  the  stems  of 
the  succeeding  year.  By  means  of  its  underground  stem  the 
13 


178  Minnesota  Plant  Life. 

spore-producing  generation  of  the  plant  is  perennial,  but  the 
sexual  plants  die  after  they  have  performed  their  functions. 

Male  and  female  plants.  It  is  now  possible  to  understand 
the  meaning  of  the  curious  sensitive  appendages  of  the  spores. 
The  spores  when  ejected  are  separated  from  each  other  into  little 
groups  by  the  writhing  of  their  appendages.  The  individual 
spores  are  not,  however,  entirely  isolated,  and  that  degree  of 
moisture  which  is  favorable  for  germination  impels  the  append- 
ages to  pull  the  neighboring  spores  close  together,  so  that  when 
they  germinate,  male  and  female  plants  shall  not  be  too  far  apart 
for  the  convenience  of  the  swimming  sperm.  This  is  a  very  good 
example  of  the  extraordinary  adaptive  relations  which  come  to 
exist  between  sexual  and  spore-producing  plants  of  the  same 
species.  The  appendages  of  the  spores  have  seemingly  no  mean- 
ing in  the  life-history  of  the  spore-producing  plant  itself,  but  they 
function  in  such  a  way  that  the  task  of  the  sperm-producing  plant 
is  made  easier  and  thus  the  development  of  fecundated  eggs  is 
insured,  for  the  perpetuation  of  successive  generations.  Upon 
clay  banks,  where  there  are  shade  and  moisture,  one  will  often 
find  among  the  young  scouring-rushes  or  horse-tails  some  of 
the  tiny  sexual  plants  looking  very  much  like  diminutive  liver- 
worts as  they  lie  more  or  less  prostrate  upon  the  soil. 

Different  sorts  of  horse-tails  and  scouring-rushes.  The  dif- 
ferent kinds  of  horse-tails  and  scouring-rushes  in  Minnesota  are 
distinguished  by  slight  structural  peculiarities  that  need  not  be 
discussed  in  detail.  The  rigid,  jointed,  unbranched  forms,  three 
or  four  feet  in  height,  which  grow  along  shaded  banks  are  per- 
haps, in  their  tissues,  the  richest  in  silica  or  sand,  and  are  the 
ones  which  have  particularly  merited  the  name  of  scouring- 
rushes.  The  very  much  branched  variety  which  is  such  an  abun- 
dant weed  in  neglected  fields,  along  roadsides,  and  in  the  edges 
of  woods,  is  a  different  species.  A  third  species,  in  which  the  lat- 
eral branches  curve  downward  in  a  characteristic  way,  is  abun- 
dant in  northern  woods  and  is  named  the  forest  horse-tail.  Still 
another  kind  is  often  found  growing  at  the  edges  of  ponds  and 
streams,  now  and  then  forming  great  patches  in  bays  and  occu- 
pying the  same  general  position  that  is  ordinarily  selected  by 
bulrushes.  This,  which  may  be  termed  the  water  horse-tail,  is 
commonly  not  very  much  branched  although  under  certain 


Minnesota  Plant  Life. 


179 


growth-conditions  it  is  capable  of  branching  almost  as  abun- 
dantly as  the  field  horse-tail.  A  curious  dwarf  variety  two  or 
three  inches  high  is  sometimes  found  growing  in  tufts  in  deep 
woods.  It  is  reported  from  the  St.  Croix  river  valley,  but  I 
have  not  seen  authentic  specimens  of  it  from  Minnesota. 

Underbrush  habits  of  horse-tails.  When  the  branched  va- 
rieties of  horse-tails  grow  in  the  edges  of  woods  they  often  be- 
come very  much  taller  than  in  fields.  This  they  accomplish  by 
thrusting  out  their  rigid  side-branches  in  every  direction  and 
permitting  them  to  rest  upon  the  twigs  of  surrounding  shrubs 
or  herbs.  Thus  they  can  distribute  their  weight  in  such  a  way 
that  the  main  stem  is  relieved  and  the  axis  may  extend  itself 
vertically  farther  than  otherwise.  Plants  which  lean  in  such 
fashion  upon  surrounding  plants  are  known  as  braced-plants. 
They  are  not  exactly  dependent  for  their  well-being  upon  the 
presence  of  other  plants  as  are  the  climbers  and  twiners,  but 
they  do  derive  some  advantage  from  their  habit  of  letting  a 
portion  of  their  weight  rest  upon  plants  near  them. 

It  is  really,  if  one  stops  to  think  of  it,  quite  as  much  of  an 
engineering  problem  to  erect  a  slender  stem  as  to  build  an  Eifel 
tower,  and  it  is  no  less  impossible  to  extend  a  leaf  into  the  air 
without  due  regard  to  the  strength  of  materials  than  it  would 
be  to  build  a  cantilever  bridge  from  wet  paper.  Plants  mani- 
fest architectural  design  and  the  problems  of  structural  engi- 
neering are  not  at  all  unlike  those  requiring  solution  by  the 
human  architect  or  bridge-builder  when  he  enters  upon  the 
plans  of  a  new  .structure.  So  it  is  obvious  that  the  bracing  of  the 
side  branches  of  horse-tails,  thus  diminishing  the  strain  upon 
the  main  axis,  might  enable  it  under  the  same  general  type  of 
structure,  to  reach  a  greater  elevation  into  the  air.  In  South 
America,  by  bracing  devices  scouring-rushes  grow  to  a  height 
of  twenty  or  thirty  feet,  though  they  are  not  thicker  than  an 
ordinary  walking-stick.  Where  the  forest  is  dense  and  dark 
such  a  plan  is  seen  to  be  highly  advantageous  and  perhaps  even 
necessary,  but  in  the  lighter,  thinner  forests  of  Minnesota  there 
is  no  need  of  such  extreme  length. 


Chapter  XX. 

What  Seeds  are  and  how  they  are  Produced. 


About  150,000  different  kinds  of  plants  produce  seeds.  A 
seed  may  be  defined  as  a  young  plant  and  its  reserve-food- 
material  enclosed  within  a  normally  protective  layer.  Some- 
times the  food-material  is  deposited  beside  or  around  the 
plantlet,  as  in  the  seeds  of  Indian  corn  and  wheat.  Again  the 
food-material  may  be  collected  in  the  plantlet  itself,  giving  to 
it  a  white,  meaty  appearance,  and  pumpkin  and  bean  seeds  are 
of  this  structure.  It  is  a  mistake  to  say  that  plants  grow  from 
the  seed,  or  rather  it  is  a  half-truth,  for  the  question  is  whence 
did  the  plantlet  come  that  is  already  present  in  the  seed  and 
needs  only  to  renew  its  development  when  the  seed  germinates? 
This  can  be  answered  in  a  word.  Leaving  out  of  considera- 
tion some  abnormal  or  peculiar  conditions  of  development,  it 
may  be  said  that  all  plantlets  in  seeds  arise  from  eggs.  The 
next  question  is  whence  comes  the  egg  from  which  the  plantlet 
in  a  seed  develops?  The  reply  is,  that  the  egg,  as  in  all  other  in- 
stances, is  produced  in  the  body  of  a  female  plant.  Still  an- 
other question — where  is  one  to  look  for  the  female  plant  of  a 
rose  or  willow,  or  any  other  seed-producing  species?  To  this 
inquiry  the  answer  is,  the  female,  like  all  other  females  in  the 
great  series  of  terrestrial  plants,  develops  from  a  spore.  Again, 
one  inquires,  where  is  the  spore  to  be  sought?  To  this  is  the 
response  that  it  is  formed  in  the  young  ovule  or  rudimentary 
seed,  occurring  as  a  more  or  less  oval,  cylindrical  or  elongated 
cell  in  the  centre  of  the  seed-rudiment. 

What  then  is  the  seed-rudiment?  It  is  a  spore-case  which 
produces  at  its  centre  the  single,  large,  thin-walled  spore.  In 
seed-plants  such  a  spore  is  called  an  embryo-sac  and  it  may 
easily  be  found  by  opening  young  pine-seeds  in  cones  not  more 
than  twelve  months  old.  Unlike  the  large-spores  of  the  smaller 


Minnesota  Plant  Life. 


181 


club-moss,  these  seed-plant  spores  are  not  ejected  from  their 
spore-cases,  while,  just  as  in  the  smaller  club-moss,  they  de- 
velop females  which  are  retained  within  the  spore-wall  and  upon 
the  bodies  of  these  females  egg-cells  are  formed.  How  is  it 
possible  for  such  an  egg,  developed  and  retained  within  the 
tissues  of  a  spore-case,  to  ob- 
tain fecundation?  Here  comes 
into  play  an  adaptation  on  the 
part  of  the  male-plants  of  the 
seed  -  producing  varieties. 
Where  is  one  to  look  for  the 
male  cottonwood  tree?  Like 
other  male  plants  it  originates 
from  a  spore,  not,  however, 
the  large-spore,  enclosed  in  the 
rudimentary  seed,  but  the 
small-spore  known  as  the  pol- 
len-grain, developed  in  large 
numbers  upon  special  leaves 
known  as  stamens.  What  sort 
of  a  plant  arises  when  a  pollen 
spore  germinates?  Before  re- 
plying to  this  question  another 
must  be  asked.  Where  does  a 
pollen-spore  germinate?  Not 

Upon   the   Soil,   Or  in   the   Water,     FlG-  «•     Diagram  of  an  ovary,  with  one  seed- 
rudiment,   in  a  higher  seed-plant,     s.  The 

as  did  the  small-spores  of  ferns 


stigma,  where  two  pollen-spores  have  germi- 
nated; o,  wall  of  ovary;  f,  stalk  of  ovule; 
ai  and  ii,  rudimentary  seed-coats;  n,  spore- 
case,  with  single  large  spore,  which  has 
germinated  to  produce  the  reduced  female 
plant;  k,  the  egg;  e,  the  body  which  forms 
the  albumen;  b,  other  cells  of  the  female. 
The  male  plant  is  shown  as  a  tubular 
thread  growing  towards  the  egg.  After 
Atkinson. 


and  smaller  club-mosses,  but 
upon  a  certain  portion  of  the 
body  of  a  spore-producing 
plant  of  its  own  species,  a  part 
usually  in  close  proximity  to 
the  rudimentary  seeds.  This 
area  upon  which  a  spore  of  the  smaller  kind  is  able  to  germinate 
is  known  as  the  stigma  in  higher  flowering  plants,  but  in  the 
lower  families  the  pollen-spores  fall  immediately  upon  the  im- 
mature seeds. 

Breeding  habits  of  seed-plants.    Returning  now  to  the  ques- 
tion, what  sort  of  a  plant  arises  when  a  pollen-spore  germinates, 


1 82  Minnesota  Plant  Life. 

the  reply  is,  a  delicate  thread,  like  a  cobweb,  comes  into  exist- 
ence and  grows  much  as  a  parasitic  fungus  filament  would 
grow  through  the  tissues  of  the  immature  fruit  down  to  the 
surface  of  the  large-spore,  imbedded  in  the  rudimentary  seed. 
By  this  time  the  female  has  developed  within  the  large-spore  and 
has  produced  her  egg.  The  end  of  the  pollen-tube,  as  the  male  is 
termed,  penetrates  the  wall  of  the  large-spore  and  transfers  a 
male  nucleus,  or  sperm,  which  fuses  with  the  egg  and  thus 
fecundation  is  accomplished.  Then  the  egg  becomes  an  embryo 
which  grows  and  produces  a  short  stem,  one  or  more  seed- 
leaves  (in  most  plants)  and  a  root.  While  the  embryo  is  devel- 
oping, the  tissues  of  the  spore-case  and  the  membranes  sur- 
rounding it  become  modified  into  the  outer  layers  or  seed-coats. 
When  the  embryo  pauses  in  its  growth  and  passes  into  a  tem- 
porary dormant  condition  the  seed  is  said  to  be  ripe.  It  may 
not,  however,  be  able  at  once  to  germinate. 

If  the  reader  has  closely  followed  this  explanation  he  will 
be  aware  that  is  is  improper  to  call  a  pollen-producing  plant 
a  male  and  he  will  understand  that  there  is  no  comparison  at 
all  between  the  sowing  of  pollen-spores  on  a  stigma  where 
they  are  to  germinate  and  a  breeding  habit,  although  the  older 
botanists  supposed  that  such  analogy  existed.  It  is  found  that 
seed-producing  plants,  like  the  smaller  club-mosses,  have  two 
sorts  of  spores,  small-spores  producing  males,  and  large-spores, 
females.  As  in  the  lower  type,  so  also  in  the  seed-plant,  there  is 
a  retention  of  the  female  within  the  wall  of  the  spore  from  which 
she  originated.  Unlike  the  smaller  club-mosses,  the  male  plant 
is  not  retained  within  the  wall  of  the  small-spore,  but  pro- 
trudes in  the  form  of  a  thread  of  miscroscopic  minuteness.  The 
retention  of  the  large-spore  within  its  spore-case,  together  with 
the  adaptation  of  the  male  plant  so  that  fecundation  may  take 
place  without  the  opening  of  either  the  large-spore  or  its  case, 
lays  the  foundation  for  that  compound  and  complex  body,  the 
seed. 

By  these  devices  the  embryo  is  kept  in  close  proximity  to 
the  vegetative  areas  of  its  species  and  in  a  pine  seed  there  are 
represented  three  successive  generations.  The  coats  of  the  seed 
and  sometimes  a  portion  of  the  food-supply,  as  in  water-lilies, 
belong  to  the  older  spore-producing  generation,  for  they  are 


Minnesota  Plant  Life.  183 

parts  of  the  same  plant  that  produced  the  large-spore.  The 
meat  of  the  seed,  or  albumen,  belongs  to  the  female,  for  it  is 
produced  within  the  large-spore  as  it  germinates.  The  embryo 
plantlet  of  the  seed  belongs  to  the  new  spore-producing  genera- 
tion and  arises  by  the  segmentation  of  an  egg.  After  it  has 
renewed  its  development — when  the  seed  has  germinated  and 
the  plantlet  has  become  old  enough — it  will  be  able  in  its  turn 
to  produce  spores.  Therefore,  the  life-history  of  a  cottonwood, 
for  illustration,  is  twice  as  complex  as  that  of  a  man.  While 
there  are  only  two  kinds  of  individuals  in  the  human  species, 
there  are  four  in  the  cottonwood:  first,  the  pollen-producing 
tree  or  staminate  cottonwood;  second,  the  seed-rudiment-pro- 
ducing tree  or  pistillate  cottonwood;  third,  the  male  cotton- 
wood  or  pollen-tube  arising  from  the  pollen-spore  and  growing 
as  a  parasite  upon  the  tissues  of  the  young  cottonwood  fruit; 
fourth,  the  female  cottonwood,  a  microscopic  plant  inclosed  in 
her  spore  deep  within  the  rudimentary  seed.  Indeed  there  may 
even  be  five  kinds  of  cottonwoods,  for  in  higher  seed-producing 
plants  there  is  strong  reason  to  suppose  that  the  albumen  of  the 
seed  is  in  reality  a  degenerate  plantlet — a  twin  brother  of  the 
embryo — produced  from  an  egg,  rather  than,  as  in  the  pines,  a 
portion  of  the  female  plant-body. 

From  this  discussion  it  will  be  seen  how  inaccurate  is  the 
common  statement  that  higher  plants  grow  from  seeds  while 
lower  plants  are  produced  by  spores  and  it  is  understood  how 
erroneous  is  the  phrase,  so  general,  especially  in  popular  works, 
that  the  spores  are  the  seeds  of  the  fungi  or  ferns.  The  higher 
plants  produce  spores  just  as  truly  as  do  the  lower  plants, 
but  in  the  former  a  peculiar  relation  of  dependence  has  come 
to  exist,  precisely  the  reverse  of  that  which  was  observed  in  the 
liverworts.  In  the  latter  the  capsular  plants,  that  is,  the  spore- 
producing  plants,  were  dependent  upon  the  sexual  plants  for 
their  food-supply  and  remained  perched  upon  their  bodies  all 
through  life.  In  the  club-moss  group  these  little  perched  plants 
learned  how  to  maintain  an  entirely  independent  existence  and 
put  forth  leaves  and  roots  of  their  own.  In  the  seed-plants  they 
have  become  so  important  and  powerful  that  they  do  all  the 
vegetative  work  of  their  species  while  the  once  stronger  and 
larger  sexual  plants  are  reduced  to  microscopic  structures  of 


184  Minnesota  Plant  Life. 

an  altogether  dependent  life-habit.  A  few  definitions  may  not 
here  be  out  of  place  and  will  be  given  in  as  tmtechnical  language 
as  possible. 

Definitions  of  certain  words.  Pollen  is  a  dust  consisting  of 
small  spores,  capable,  upon  germination,  of  producing  male 
plants.  The  embryo-sac  is  a  large-spore  developed  in  the  rudi- 
mentary seed  and  capable  of  producing  a  female.  The  pollen- 
spores  are  produced  in  special  spore-cases  situated  on  leaf-like 
organs  called  stamens.  The  embryo-sacs  are  commonly  pro- 
duced singly  in  bodies  called  ovules  borne  upon  leaves  known 
as  carpels.  An  axis  upon  which  stamens  or  carpels  or  both  are 
generated  is  called  a  flower.  An  ovule  which  has  matured, 
normally  as  the  result  of  a  breeding  act,  is  called  a  seed.  The 
carpel,  or  carpels  of  a  flower  with  the  enclosed  seeds,  is  called 
a  fruit. 

Two  series  of  seed-producing  plants.  There  are  two  series 
of  seed-producing  plants,  the  lower,  in  which  the  pollen-spores 
fall  directly  upon  the  immature  seeds  and  germinate,  and  the 
higher,  in  which  the  carpels  close  around  the  immature  seeds 
and  the  pollen-spores  fall  and  germinate  upon  a  special  portion 
of  the  carpel  or  carpels  known  as  the  stigma. 


Chapter  XXI. 

Ground-hemlocks  and  various  Pines, 
if 

Of  lower  seed-plants  there  are  five  living  and  at  least  two 
extinct  families.  In  Minnesota  but  two  of  the  five  living  fam- 
ilies are  represented.  These  are  the  yews  and  the  pines. 

Ground-hemlocks.  The  yews  are  represented  by  a  single 
species,  the  ground-hemlock,  a  well-known  plant  of  wooded 
banks  and  forests  throughout  most  of  the  state.  In  England 
a  species  of  yew  exists  which  becomes  a  large  tree,  but  of  the 
four  species  in  America  none  reaches  any  very  great  size,  and 
the  ground-hemlock  is  the  smallest  of  the  group.  It  is  an  ever- 
green shrub  with  leaves  much  like  those  of  the  balsam,  and  rec- 
ognized by  its  crimson  berries  the  size  of  small  gooseberries. 
The  berry  of  the  yew,  however,  is  not  a  fruit  but  a  seed,  sur- 
rounded by  a  red  pulp-cup  which  may  be  regarded  as  a  basal 
outgrowth.  Of  all  seed-producing  plants  in  the  state  the  yew 
gives  its  seeds  the  least  protection.  In  pines  the  seeds  are  en- 
closed by  the  scales  of  the  cone,  and  in  all  higher  seed-plants  the 
seeds  are  developed  within  fruits  and  are  never,  from  the  first, 
exposed,  as  in  the  ground-hemlock.  The  red  pulp  which  en- 
circles the  yew  seed  makes  it  attractive  to  birds  and  it  is  dis- 
seminated by  their  agency.  Besides  the  seed-rudiments  on 
the  branches,  the  yew  produces  little  round  cones  consisting  of 
axes  upon  which  are  borne  a  few  shield-shaped  leaves.  Each 
of  these  resembles  the  spore-producing  leaves  of  the  scouring- 
rush  and  on  the  under  side  of  each  a  circle  of  pollen-spore-cases 
are  developed.  The  yew  plants,  of  all  Minnesota  seed-bearing 
forms,  produce  the  largest  number  of  pollen-spore-cases  on  a 
single  stamen.  Usually  the  number  is  four,  often  but  two,  while 
in  the  yew  the  number  may  be  six  or  even  more.  The  micro- 
scopic male  and  female  yew  plants  are  short-lived,  but  the  spore- 
producing  plant,  beginning  as  an  embryo  in  the  seed,  then  after 


1 86  Minnesota  Plant  Life. 

the  germination  of  the  seed  achieving  independence,  is  a  long- 
lived  shrub  of  somewhat  prostrate  habit,  and  with  dark-green 
leaves  and  tough-fibred  wood  in  which  resin  does  not  occur, 
while  it  does  in  plants  of  the  related  pine  family. 

Pines  of  different  sorts.  The  pine  family  includes  13  or  14 
Minnesota  species  out  of  a  total  of  about  300  distributed  over 
all  parts  of  the  world.  In  these  the  rudimentary  seeds  are  pro- 
duced upon  the  inner  sides  of  scales  or  carpels  which,  like  the 
stamens,  are  aggregated  into  cones.  The  pines  and  their  allies 
may  therefore  be  said  to  produce  two  kinds  of  flowers,  stami- 
nate  and  pistillate. 

Among  the  members  of  the  pine  family  in  Minnesota  may 
be  mentioned  the  tamarack,  a  deciduous  tree  of  social  habit; 
the  pines  of  which  three  varieties,  the  white,  the  jack  and  the 
red  or  Norway,  grow  within  the  borders  of  the  state  and  are 
dominant  species  of  the  northern  forest;  the  spruces,  of  which 
there  are  three  varieties,  the  black,  the  white  and  the  muskeg; 
the  balsam  or  fir,  common  in  swamps;  the  white  cedar  or 
arbor-vitae,  a  tree  that  flourishes  best  in  the  northern  part  of 
the  state;  the  hemlock,  very  rare  in  Minnesota,  but  occurring 
in  two  isolated  patches  in  St.  Louis  county  and  Carlton  county ; 
and  the  junipers,  of  which  there  are  four  species,  one  tree-like 
in  habit  and  known  as  the  red  cedar,  the  others  low  shrubs  and 
called  savins  or  junipers. 

The  white  pine.  Among  all  these  plants  the  white  pine,  the 
most  important  timber  tree  of  -the  state,  is  of  especial  interest. 
Its  wood  is  light,  resinous  and  easily  worked.  It  is  used  in  the 
manufacture  of  lumber,  laths,  shingles,  matches,  sashes,  doors, 
blinds,  woodenware,  telegraph  poles  and  the  masts  of  ships. 
Many  millions  of  dollars  are  invested  in  mills  for  its  manu- 
facture into  lumber,  and  in  railways  for  the  transportation  of 
the  logs.  This  tree  often  grows  over  a  hundred  feet  in  height 
with  a  trunk  sometimes  more  than  three  feet  in  diameter.  Its 
bark  is  rough  and  deeply  divided  by  clefts.  When  growing  in 
the  open,  as  sometimes  upon  hills,  for  example,  near  lake  shores 
in  Cass  county,  the  lower  branches  are  much  prolonged  and 
the  whole  tree  has  a  broadly  conical  form.  But  when  a  native 
of  the  forest  the  lower  branches  become  shaded  out  of  existence 
and  the  tree  has  the  well-known  compressed  slender  appear- 


Minnesota  Plant  Life. 


ance.  The  topmost  branches  usually  dispose  themselves  in  a 
flamboyant  manner,  which  makes  it  possible  to  recognize  this 
variety  of  pine  as  tar  as  it  can  be  seen.  The  leaves  are  slender 
prismatic  needles,  borne  in  groups  of  five,  on  special  short 
branches.  They  are  of  a  somewhat  bluish-green  color,  and  dur- 
ing their  first  winter  are  inclosed  in  small  bright  green  buds. 
The  staminate  cones  are  light-brown,  egg-shaped,  about  a  third 
of  an  inch  long  and  mature  in  a  single  season.  The  pistillate 
cones  are  somewhat  smaller  at  first,  of  a  purplish  color  and 
borne  on  the  topmost  branches  of  the  tree,  while  the  staminate 
cones  are  usually  developed  on  the  lower  branches.  Originally 
the  pistillate 
cones  are  erect, 
but  during  the 
first  year  of 
their  lives  they 
become  heavier 
and  take  a  hori- 
zontal position. 
At  this  time 
they  are  nearly 
an  inch  in 
length.  The 
next  year  they 
grow  rapidly, 
become  pendu- 
lous, and  reach  their  full  size  in  mid-summer.  They  are  now  six 
inches  in  length  and  seven-eighths  0f  an  inch  or  thereabout  in 
diameter.  During  the  autumn  of  the  second  year,  they  open  and 
scatter  their  brown  seeds,  each  of  which  is  furnished  with  a  del- 
icate wing  by  means  of  which  it  is  disseminated  by  the  wind. 
Within  the  seed  will  be  found  an  edible  albumen,  with,  however, 
a  strongly  resinous  odor,  and  in  the  centre  of  this  stands  the 
straight  young  pine  with  from  eight  to  ten  seed-leaves  growing 
in  a  crown  about  the  short  apex  of  its  stem.  The  root,  before 
it  issues  from  the  seed,  is  already  provided  with  a  root-cap  and 
the  stem-area  below  the  seed-leaves  is  short.  The  white  pine 
contains  more  resin  than  any  other  variety,  yet  it  is  not  ordi- 
narily used  in  the  manufacture  of  turpentine  as  is  the  pitch  pine 
of  the  south. 


FIG.  70.    White  pines  on  the  rocks  at  Taylor's  Falls, 
graph  by  Williams. 


After  photo- 


1 88 


Minnesota  Plant  Life. 


Pine  trees  do  not  spring  up  again  after  fires  with  nearly  the 
vigor  possessed  by  a  number  of  hardwood  trees.  In  Minne- 
sota hundreds  of  thousands  of  young  trees  are  annually  de- 
stroyed by  fire  and  their  place  is  occupied  by  plants  which  are 
comparatively  worthless  in  the  commerce  of  the  state. 

The  Norway  or  red  pine.  The  other  commercial  pine  of 
Minnesota  is  a  somewhat  smaller  tree,  averaging  fifty  to  eighty 
feet  in  height.  This  is  commonly  called  the  Norway  pine  by  log- 
gers, though  a  more  correct  name  would  be  red  pine.  The  bark 
is  of  a  reddish  tint  and  much  smoother  than  that  of  the  white 
pine.  When  standing  in  groves  the  tops  of  the  red  pines  are 

round,  not  irregular  and  crested 
as  are  the  tops  of  the  white  pine. 
The  leaves  are  produced  in  pairs 
on  short  special  branches.  They 
are  dark-green,  five  or  six  inches 
in  length  and  shaped  somewhat 
like  half-cylinders.  The  stami- 
nate  cones  are  longer  and  slen- 
derer than  those  of  the  white 
pine,  grow  in  more  elongated 
clusters  and  are  of  a  purplish 
color.  The  pistillate  cones  are 
at  first  almost  spherical,  red  in 
color  and  a  quarter  of  an  inch  or 
more  in  length.  Like  cones  of 
the  white  pine  these  pistillate 
flowers  take  two  years  to  mature  and  finally  drop  from  between 
their  scales  the  smaller,  darker  seeds  with  wings  shaped  differ- 
ently from  those  of  the  white  pine  seeds.  The  seedling  plant 
has  fewer  seed-leaves  and  is  limited  to  eight,  while  five,  six 
or  seven  are  more  common  numbers.  The  \vood  is  not  so 
easily  worked  as  that  of  the  white  pine,  nor  do  the  logs  float 
so  well  in  drives.  The  timber  is,  however,  abundantly  em- 
ployed in  the  manufacture  of  buildings,  trestles  and  sometimes 
in  railway  construction. 

The  jack  pine.  The  third  species  of  pine  in  Minnesota,  the 
jack  pine,  is  very  prevalent  in  sandy  soil  throughout  the  north- 
ern part  of  the  state.  It  is  a  smaller  tree  than  either  of  the 


FIG.  71. 


Jack  pine.    After  Britton  and 
Brown. 


Minnesota  Plant  Life.  189 

others,  but  may  in  groves  reach  the  height  of  seventy  or  eighty 
feet.  The  top  is  more  pointed  or  spire-like  than  that  of  the  red 
pine  and  the  bark  is  rather  thin  and  irregularly  divided,  a  little 
like  elm  bark.  The  leaves  arise  in  pairs  and  are  much  shorter 
than  those  of  the  red  pine,  varying  from  three-quarters  of  an 
inch  to  one  and  a  quarter  inches  in  length.  The  staminate 
cones  are  produced  in  clusters  much  like  those  of  the  red  pine, 
but  smaller.  The  pistillate  cones  are  nearly  spherical  in  shape, 


FIG.  72.     Rock-vegetation  near  Duluth.     White  pines,  white  cedars  and  junipers.     After  pho- 
tograph by  Williams. 

purple  in  color  and  appear  on  the  topmost  branches  of  the  tree. 
When  the  pistillate  cones  mature  during  the  second  season  of 
their  lives  they  are  generally  curved  to  one  side,  by  which  char- 
acter they  may  be  recognized  and  distinguished  from  the  short 
cones  of  the  red  pine.  The  seeds  are  small,  winged,  and  black- 
ish in  color  and  the  embryo  plantlet  has  only  four  or  five  seed- 
leaves.  There  is  no  difficulty  in  discriminating  even  between 
the  seedlings  of  the  three  species.  The  wood  of  the  jack  pine 


190  Minnesota  Plant  Life. 

is  not  strong  and  is  little  used  as  lumber,  though  it  is  cut  for 
firewood  in  some  parts  of  the  state  and  occasionally  employed 
in  the  manufacture  of  posts  or  ties.  This  pine  is  particularly 
abundant  in  the  region  around  Brainerd,  where  it  covers  hun- 
dreds of  square  miles  in  an  almost  unbroken  forest. 

The  white  cedar.  The  white  cedar  or  arbor-vitse  is  a  tree 
fifty  or  sixty  feet  high  with  a  short,  thick  trunk.  It  is  especially 
abundant  in  the  far  northern  region  of  the  state,  not  coming 
south  so  readily  as  the  pines.  It  is  prominent  along  lake  shores 
on  the  international  boundary  and  its  branches  jutting  out  over 
the  water  make  picturesque  scenery  on  the  shores  of  most  lakes 
east  of  Rainy  lake.  The  leaves  are  large  and  remote  on  older 
shoots,  but  on  the  younger,  which  are  arranged  in  flat,  fern- 
like  groups,  they  are  short  and  tightly  lapped  over  each  other 
like  shingles.  The  flowers,  opening  in  the  spring,  are  purple 
in  color  and  the  fruits  ripen  in  a  single  year.  The  seeds  are 
winged  along  both  margins,  thus  differing  from  the  pines  in 
which  the  wings  are  principally  terminal,  and  are  only  an  eighth 
of  an  inch  long.  Seedling  plants  of  the  white  cedar  have  but 
two  seed-leaves,  in  this  respect  resembling  most  higher  seed- 
plants.  The  wood  is  very  light  and  peculiarly  durable,  sweet- 
scented  and  brown  in  color.  It  is  highly  prized  for  railway  ties, 
shingles  and  fencing  lumber  and  is  used  by  the  Indians  in  the 
manufacture  of  paddles  and  as  ribs  for  their  canoes.  They  em- 
ploy also  the  inner  bark  in  the  manufacture  of  mats,  cutting  it 
up  into  strips  which  they  dye  and  plait  elaborately  in  quaint 
and  traditional  patterns.  Young  arbor-vitae  plants  are  used  in 
Minnesota  for  hedges. 

The  hemlock.  The  hemlock  is  a  tree  sometimes  no  feet  in 
height  with  a  trunk  four  feet  in  diameter,  but  in  Minnesota,  in 
the  two  small  patches  where  it  is  known,  it  does  not  reach  this 
size.  The  lower  branches  are  generally  drooping  and  the  leaves 
are  short  and  flat,  dark-green  above  and  lighter  below.  The 
cones  are  slightly  longer  than  the  leaves.  The  wood  is  soft 
and  light,  brown  or  white  in  color  and  the  general  appearance 
of  the  twigs  with  their  foliage  is  quite  similar  to  that  of  the 
ground-hemlock — hence  the  common  name  of  the  latter.  The 
two  plants,  however,  are  really  members  of  different  families. 
Hemlocks  are  of  much  economic  importance  from  their  bark, 


Minnesota  Plant  Life. 


191 


to  the  exclusion  of  other  varieties,  being  employed  in  tanning. 
The  substance  known  as  tannin  is  abundant  in  hemlock  bark 
and  by  its  action  upon  hides  they  are  cured  and  converted  into 
leather. 

The  tamarack.  The  tamarack  differs  from  the  other  Min- 
nesota pines  in  its  habit  of  shedding  its  leaves  in  autumn.  The 
leaves  are  never  of  the  dark  rich  green  of  the  spruces,  firs  or 
pines,  but  are  of  a  paler  color.  In  autumn  they  turn  golden  yel- 
low before  they  fall  and  after  the  severe  frosts  of  November 


FIG.  73.     Tamarack  swamp  with  sedge  border.    After  photograph  by  Williams. 

they  separate  from  the  twigs  by  means  of  cork  layers  and  the 
tree  passes  the  winter  in  a  leafless  condition.  Tamaracks  oc- 
cupy wet  ground,  forming  by  their  growth  the  well-known 
feature  of  the  landscape  known  as  the  tamarack  swamp.  The 
cones  of  the  tamaracks  are  small.  The  wood  is  hard,  resinous 
and  durable,  weighing  twice  as  much  as  that  of  white  cedar,  and 
is  used  in  the  manufacture  of  railway  ties,  as  fence  poles  and 
for  fire-wood.  Occasionally,  too,  it  is  manufactured  into  tele- 
graph poles. 


192  Minnesota  Plant  Life. 

The  spruces.  The  spruces  are  known  for  their  spire-like 
habit  of  growth  and  serve  as  the  Christmas  trees  of  the  children. 
They  do  not  grow  to  any  great  size  in  Minnesota  although  the 
white  spruce  under  suitable  conditions  may  reach  a  height  of 
150  feet.  In  Minnesota  the  black  spruce  seems  to  be  rather 
more  frequent  and  together  with  tamaracks,  or  to  their  exclu- 
sion, forms  characteristic  swamp  growths,  the  trees  standing 
very  close  together.  A  slightly  different  variety,  the  muskeg 
spruce,  with  peculiar  drooping  branches  is  particularly  abundant 
in  such  localities.  Spruce  leaves  are  short  and  four-sided, 
spreading  in  all  directions  from  the  twig.  The  cones  are  small 
and  plump,  with  shell-shaped  scales  closely  lapping  over  each 
other.  In  the  white  spruce  the  cones  are  oblong  and  some- 
what cylindrical  in  form,  while  in  the  black  spruce  and  muskeg 
spruce  they  are  egg-shaped  in  general  outline.  When  the 
leaves  of  the  black  spruce  die  they  fall,  leaving  little  hummocks 
on  the  twigs.  None  of  these  plants  except  the  true  pines  has 
special  leaf-bearing  branches  which  separate  as  a  whole  when 
the  leaves  have  finished  their  work. 

The  balsam.  The  balsam  or  fir  is  a  slender  tree  growing  in 
somewhat  drier  soil  than  that  preferred  by  the  tamaracks  and 
black  spruces.  In  Minnesota  it  rarely  exceeds  a  height  of  40 
feet.  The  leaves  are  flat  and  sessile,  arranged  apparently  in 
rows  right  and  left  on  the  twig,  but  really  in  spirals.  The  twigs 
have  a  much  flatter  look  than  the  twigs  of  spruces.  Only  one 
species  occurs  in  Minnesota  and  this  has  a  smooth  bark  in  which 
resinous  blisters  are  formed.  The  whole  plant  is  sweet-scented 
and  the  wood  is  .soft  and  light.  From  the  resin  blisters  is  de- 
rived the  product  known  as  Canada  balsam.  The  balsam  tree 
may  be  known  from  the  spruces  by  its  erect  cones  as  well  as 
by  the  flat  branch  systems,  for  in  spruces  the  cones  are  pendu- 
lous. 

The  junipers  and  red  cedar.  There  remain  to  be  men- 
tioned the  junipers,  a  group  of  evergreens  remarkable  for  trans- 
forming their  pistillate  cones  into  little  round  blue  berries.  The 
scales  of  the  cone  become  fleshy,  inclosing  the  seeds.  They  are 
fragrant  and  an  extract  of  juniper  is  used  in  the  flavoring  of  gin. 
Birds  pick  the  berries,  thus  providing  for  the  distribution  of  the 
seeds.  Therefore,  as  one  would  expect,  the  seeds  are  not  winged 


Minnesota  Plant  Life. 


193 


as  in  most  of  the  other  pines.  One  of  the  junipers,  the  red 
cedar,  grows  in  Minnesota  as  a  tall  tree.  It  is  not  very  com- 
mon in  the  state,  but  is  found  at  Redwood  Falls  and  on  lake 
shores  and  bluffs  at  a  few  isolated  localities  in  the  southern 
part.  The  leaves  are  short  and  broad  with  sharp  points  and 
are  developed  in  four  rows.  The  red  cedar  is  the  most  widely 
distributed  plant  of  its  family  in  North  America.  The  wood  is 
light,  perfumed,  of  a  reddish  color,  except  in  the  outer  layers, 
where  it  is  white.  It  is  largely  used  in  cabinet  making,  in  the 


FIG.  74.     Red  cedars  on  the  banks  of  a  Minnesota  lake.     After  photograph  by  Williams. 

manufacture  of  lead  pencils,  and  is  believed  to  be  so  particularly 
distasteful  to  moths  that  closets  in  which  woolen  clothing  and 
furs  are  to  be  hung  during  the  summer  months  are  sometimes 
lined  with  it. 

The  other  junipers  of  the  state  are  low  shrubs.  One  is  char- 
acterized by  spreading  awl-shaped  leaves  arranged  in  whorls  of 
three,  and  this  form  sometimes  growls  into  a  low  tree.  The 
others  are  prostrate  shrubs  creeping  over  the  rocks  or  sand,  and 
are  abundant  in  the  northern  part  of  the  state  where  they  form 
a  distinctive  vegetation  on  some  of  the  islands  in  Lake  of  the 

14 


194  Minnesota  Plant  Life. 

Woods  and  Rainy  lake.  Their  leaves,  like  those  of  the  red 
cedar,  lap  over  each  other,  are  short  and  slightly  pointed.  They 
stand  in  four  rows,  giving  the  branch  upon  which  they  are  borne 
a  square  appearance. 

Characters  of  lower  seed  plants.  There  are  a  number  of 
features  in  which  the  yews  and  pines  agree.  The  seeds  of  each 
are  produced  in  such  a  way  that  when  young  the  pollen  spores 
may  fall  close  to  their  ends,  so  that  the  only  tissues  through 
which  the  pollen-tube  must  grow  to  reach  the  female  plant  are 
the  cells  of  the  spore-case  that  surrounds  the  large-spore  in 
which  the  female  plant  is  situated.  For  this  reason  the  lower 
seed-plants  are  sometimes  called  the  naked-seeded  plants.  While 
the  seeds  are  maturing  they  are  enclosed,  except  in  the  ground 
hemlock,  quite  as  truly  as  are  those  of  higher  forms.  In  the 
juniper-berry,  for  illustration,  when  it  is  full  grown,  the  scales 
which  constitute  the  little  fleshy  cone  are  blended  at  their  edges 
in  such  a  manner  that  the  seeds  are  entirely  enclosed  and  can- 
not at  all  be  termed  naked.  In  the  pines  proper,  too,  the  young 
cones  appress  their  scales  so  tightly  that  the  seeds  are  quite 
as  effectually  protected  as  they  would  be  in  the  closed  fruits  of 
higher  types.  At  first,  however,  even  in  the  junipers,  the  scales 
of  the  immature  cone  are  open  and  it  is  possible  for  pollen- 
spores  to  fall  between  them,  thus  reaching  the  ends  of  the  young 
seeds  growing  upon  their  inner  surfaces. 

A  character  in  which  the  lower  seed-plants  all  agree  is  the 
production  of  albumen  in  the  seed  before  the  egg  of  the  female 
is  fecundated  by  the  sperm-nucleus  of  the  pollen-tube.  In  the 
higher  seed-plants  the  albumen  of  the  seed,  when  present;  does 
not  form  until  the  egg  which  is  to  produce  the  embryo  has  re- 
ceived its  fecundation.  The  albumen  of  the  seed  may  be  re- 
garded as  the  body  of  the  female  plant  and  the  young  embryo 
nurses  upon  it  during  its  life  within  the  seed  just  as  the  young 
spore-producing  plants  of  a  liverwort  or  moss  nurse  upon  the 
vegetative  body  of  the  sexual  plants  of  their  species. 

In  still  another  respect  the  lower  seed-plants  agree  and  differ 
from  all  the  higher  seed-plants.  In  them,  on  the  body  of  the 
female  plant  produced  within  the  large-spore,  true  egg-organs 
are  formed,  each  enclosing  an  egg  and  provided  with  a  short 
neck  the  end  of  which  is  near  the  inner  surface  of  the  spore- 


Minnesota  Plant  Life. 


'95 


wall.  In  higher  seed-plants  there  is  no  definite  egg-organ,  but 
the  egg  lies  loosely  among  the  other  cells  of  the  extremely  re- 
duced and  degenerate  female. 

Relation  between  lower  seed-plants  and  primitive  seedless 
plants.  A  very  remarkable  character,  which  shows  clearly  the 
connection  between  smaller  club-mosses  and  lower  seed-plants, 
is  not  known  to  be  presented  by  either  of  the  Minnesota  fam- 
ilies of  the  latter  group,  though  it  is  now  described  for  two  that 
are  exotic.  It  is,  however,  a  fact  of  such  extreme  interest  that 
it  should  be  mentioned  at  this  point. 


FIG.  75.  Rock  on  the  St.  Croix  river,  near  Taylor's  Falls.  vShows  zonal  distribution  of  trees. 
White  pines  stand  on  top  of  the  rock,  and  birches  and  poplars  on  the  sides.  After  photo- 
graph by  Mr.  H.  C.  Cutler. 

In  the  sago-palms  and  ginkgo  trees  the  pollen-spores  fall  as 
in  other  naked-seeded  plants,  upon  the  ends  of  the  immature 
seeds,  then  germinate  and  produce  their  pollen-tubes.  In  the 
end  of  each  pollen-tube  in  these  plants  there  develop  a  pair  of 
motile  spermatozoids  provided  with  swimming  lashes.  In  the 
cycad  family  to  which  the  sago-palm  belongs,  are  a  few  Amer- 
ican species  finding  their  home  in  Florida.  In  these  when 
the  pollen-tube  comes  close  to  the  egg  a  motile  spermatozoid 
swims  into  it,  peeling  off  its  swimming-lashes  in  a  spiral  coil 


196  Minnesota  Plant  Life. 

and  leaving  them  at  the  edge  of  the  egg  just  inside  its  wall. 
The  remainder  of  the  sperm-nucleus  finds  its  way  to  the  centre 
of  the  female  cell.  In  higher  forms  of  naked-seeded  plants,  of 
which  the  yews  and  pines  are  examples,  the  swimming-lashes 
of  the  spermatozoids  seem  to  have  been  quite  abandoned.  They 
are  indeed  no  longer  necessary,  for  the  old  algal  type  of  aquatic 
reproduction  has  been  finally  outgrown.  It  is  a  most  remark- 
able and  impressive  fact  that  in  all  the  terrestrial  forms,  from 
the  liverworts  up  to  the  cycads,  including  all  the  ferns,  club- 
mosses  and  their  allies,  the  primitive  aquatic  nature  of  the  plant 
reasserts  itself  during  the  reproductive  phase  and  one  finds  such 
plants  as  the  granite-mosses,  accustomed  to  life  upon  bare,  dry 
rocks,  quite  unable  to  bring  their  sperms  and  eggs  together 
except  immediately  after  heavy  rains,  when  the  surface  of  the 
rock  is  flooded  with  water,  thus  enabling  the  aquatic  sperms  to 
use  their  swimming  threads.  This  long  persistence,  ages  after 
the  aquatic  habitat  had  been  abandoned  by  the  ancestral  algae 
from  which  the  higher  plants  are  supposed  to  have  arisen,  is  a 
striking  example  of  the  really  profound  inertia  of  living  struc- 
tures. 


Chapter  XXII. 


From  Cat-tails  to  Eel-grasses. 
if 

Higher  seed-plants.  The  characters  of  this  group  are  as 
follows :  the  rudiments  of  the  seeds  are  protected  by  the  fusing 
together  of  the  specialized  leaves  upon  which  they  are  borne 
into  a  fruit-rudiment  known  as  the  ovary.  The  leaves  which 
thus  fuse  are  called  carpels.  In  some  types  the  ovary  consists 
of  a  single  carpel,  in  others,  of  several  carpels  blended  into  a 
single  fruit-rudiment,  while  the  number  of  carpels  in  a  flower 
varies  in  the  different  families.  The  female  plant,  produced  in 
the  large-spore  of  the  seed-rudiment,  consists  of  a  few  cells, 
commonly  eight  in  number,  near  the  time  that  the  egg  is  fecun- 
dated. The  albumen  of  the  seed  is  not  of  the  nature  of  a 
female  plant,  but  is  rather  to  be  considered  as  the  twin  of  the 
embryo,  and  does  not  form  until  after  the  sperm  and  egg  have 
fused.  In  the  latter  characters  it  will  be  seen  that  the  higher 
seed-plant  differs  from  the  lower. 

The  lower  class  of  higher  seed-plants.  There  are  two  prin- 
cipal classes  of  higher  seed-plants.  The  lower  class  is  distin- 
guished by  the  production  of  embryos  with  but  a  single  seed- 
leaf.  In  such  plants  the  stem  develops  fibrous  or  woody  threads 
which  become  entirely  mature  and  do  not  blend  into  a  cylinder 
from  which  to  form  a  layer  of  growing  tissue  between  the  wood 
and  the  bark.  Hence  the  stems  of  perennial  plants  of  this  class 
do  not  show  "annual  rings"  of  growth  like  those  of  the  other 
and  higher  class.  For  the  most  part  the  leaves  have  parallel 
veins  although  some,  such  as  those  of  the  jack-in-the-pulpit,  the 
smilax  and  the  skunk-cabbage  have  netted  veins.  The  flowers 
are  ordinarily  made  up  of  five  whorls  of  leaves,  the  two  lower 
and  outer  whorls  constituting  the  perianth,  then  two  whorls  of 
stamens  and,  in  the  centre,  one  whorl  of  carpels.  The  number 
of  leaves  in  a  whorl  is  generally  three,  but  in  certain  types *the 
number  varies,  especially  in  the  three  inner  whorls,  so  that 
water-plantains,  for  example,  produce  a  large  number  of  sep- 


198 


Minnesota  Plant  Life, 


arate  carpels  at  the  middle  of  a  flower  while  grasses  produce 
but  one.  A  variety  of  plants  belonging  to  this  division  of  the 
vegetable  kingdom  exist  in  Minnesota.  The  class  is  divided 
into  orders  of  which  eleven  are  recognized,  and  the  orders  are 
divided  into  families. 

Cat-tails.  The  cat-tails  belong  to  a  small  order,  including 
also  the  bur-reeds  and  the  screw-pines,  the  latter  of  which  are 
not  represented  in  the  state.  Cat-tails,  however,  are  common 
enough  at  the  edges  of  marshes,  swamps  and  lakes,  and  a  single 
species,  the  broad-leaved  cat-tail,  is  familiar  in  such  localities. 

It  is  provided  with  a 
creeping  rootstock  which 
lies  imbedded  in  the  mud. 
The  leaves  are  slender 
and  flat,  sheathing  the 
upright  branches  of  the 
rootstock  by  their  bases. 
The  flowers  are  of  two 
sorts,  some  containing 
only  carpels  and  others 
only  stamens.  The  two 
kinds  are  produced  in  the 
same  spike-like  cluster, 
the  staminate  aggregated 
above  and  the  pistillate 
below.  The  brown  cyl- 
inder or  "cat-tail"  is  the 
compact  mass  of  pistillate 
flowers.  The  little  fruits  are  provided  with  cottony  hairs  and 
burst  when  they  have  been  lying  in  water  for  a  short  time. 
Each  seed  consists  of  a  hard  shell  within  which  is  considerable 
albumen  surrounding  a  single  embryo  plantlet. 

Bur-reeds.  There  are  at  least  six  sorts  of  bur-reeds  in  Min- 
nesota. They  occupy  similar  habitats  to  those  preferred  by 
the  cat-tails.  Their  prostrate  creeping  rootstocks  are  rooted  in 
the  mud  and  from  them  erect  branches  arise.  On  these  are 
developed  grass-like  leaves.  The  flowers  are  of  two  sorts  as 
in  the  cat-tails,  and  are  gathered  in  globular  heads,  varying  in 
size  from  a  pill  to  a  large  marble.  The  staminate  heads  are 


FIG.  76.     Bur-reed.     After  Britton  and  Brown. 


Minnesota  Plant  Life. 


199 


smaller  and  higher  on  the  stem  than  the  pistillate.  The  fruit 
has  but  a  single  cavity.  The  seeds  are  furnished  with  con- 
siderable albumen  and  within  this  the  embryo  stands  nearly 
straight.  These  plants  are  sometimes  mistaken  for  sedges,  but 
are  easily  recognized  by  their  globular  flower-heads  of  two  sorts 
on  the  same  general  branch.  Sometimes  the  heads  are  pro- 
vided with  stalks ;  in  other  varieties  they  are  sessile. 

The  second  order  in  the  ascending  series  includes  seven  fam- 
ilies, of  which  five  are  represented  in  the  Minnesota  flora. 


FIG.  77.     lyakeside  vegetation.    Just  off  shore  is  a  growth  of  the  floating  pondweed,  then  of 
arrowheads,  while  further  out  are  reeds  and  rushes.     After  photograph  by  Williams. 

Pondweeds.  These  are  for  the  most  part  submerged  plants 
growing  in  ponds,  lakes  and  slow  streams  throughout  the  state. 
About  twenty  Minnesota  species  are  known  to  exist  in  such 
localities.  They  all  root  at  the  bottom  of  the  water.  Their 
stems  are  slender,  often  branching,  and  when  taken  out  of  the 
water  are  limp,  owing  to  their  poor  development  of  woody  tis- 
sue. The  flowers  are  commonly  collected  in  spikes  which  in 
spring  are  barely  thrust  above  the  water  in  order  that  the  wind 
may  carry  the  pollen  from  the  stamens  to  the  stigmas.  These 
spikes  are  the  little  objects  upon  which  lake-flies  like  to  perch 


2OO 


Minnesota  Plant  Life. 


— as  must  often  have  been  observed  by  every  one  who  has  fished 
in  Minnesota  lakes. 

The  different  species  of  pondweeds  may  be  distinguished 
by  their  leaves.  In  one  common  variety  leaves  of  a  somewhat 
oval  shape  float  upon  the  surface  of  the  water,  but  besides  these 
there  are  present  upon  the  submerged  portions  of  the  plant 
short,  reduced,  grass-like  leaves.  In  another  with  leaves  some- 
what similar,  but  crowded  together  and  altogether  submerged, 
there  wrill  not  be  found  the  special  grass-like  leaves.  Still  an- 
other has  clearly  two  very  different  sorts  of  leaves,  some  finely 
dissected  and  others  elliptical  in  outline.  In  yet  another  the 

leaves  are  all  delicate  and  thread- 
like. A  great  variety  in  the 
shape  and  size  of  pondweed 
leaves  may  be  observed  upon 
looking  down  through  the  clear 
water  upon  s  u  b  me  r  g  e  cl  bars 
where  they  grow  so  luxuriantly. 

In  all  these  plants  the  seeds 
are  curved  or  straight  and  the 
embryo  has  no  encasement  of  al- 
bumen. The  fruit,  in  which  are 
the  seeds,  consists  of  four  little 
bodies  much  like  diminutive 
peaches.  Very  closely  related  to 

FIG.  78.     Clasping-leaved  pondweed.    After     the     pondweeds      are     the     naiads 
Britton  and  Brown.  «•••".  i-  -111 

which  may  be  distinguished  by 

the  solitary  pistil  which  forms  the  fruit.     They  grow  in  exactly 
similar  localities  and  one  species  is  common  in  Minnesota. 

Arrow-grasses.  A  third  family  is  known  as  the  arrow-grasses. 
Four  species  are  described  from  Minnesota  localities  and  are 
to  be  found  in  some  abundance  in  tamarack  swamps,  especially 
in  the  northern  part  of  the  state.  The  leaves  are  rush-like  and 
the  flowers,  arranged  in  terminal,  loose  spikes,  produce  stamens 
and  pistils  upon  the  same  axis,  while  from  three  to  six  carpels 
fuse  together  to  make  the  fruit.  One  variety  of  arrow-grass  is 
discriminated  by  the  small  number  of  flowers  in  the  spike.  All 
of  these  plants  are  perennial  and  some  of  them  are  to  be  pretty 
generally  met  with  in  all  portions  of  the  state,  while  others  are 


Minnesota  Plant  Life. 


201 


rare.     They  should  be  sought  in  rather  moist  peat-bogs  or  in 
marshes  at  the  edges  of  lakes. 

Water-plantains  and  arrowheads.  A  fourth  family  includes 
the  water-plantains,  the  arrowheads  and  a  few  related  plants 
in  which  the  flowers  are  similar  though  the  leaves  are  of  differ- 
ent appearance.  The  common  water-plantain  is  known  by  its 
large  oval  leaves,  two  or  three  inches  in  length  and  with  several 
strong  longitudinal  ribs.  The  flowering  stem  is  much  branched, 
bearing  a  number  of  pretty  flowers  each  with  three  round  white 
petals,  from  six  to  nine  stamens  and  usually  several  separate 


FIG.  79.     Evening  scene  in  Minnesota.     Arrowheads,  bulrushes  and  willows  in  foreground. 
After  photograph  by  Williams. 

carpels  which  form,  as  the  structure  matures,  a  little  fruit- 
cluster.  The  embryo  in  the  seed  is  curved  like  a  horse-shoe 
and  there  is  no  albumen.  These  plants  produce  large  masses 
or  colonies  in  favorable  localities.  They  are  abundant  in  ditches 
and  pools  and  along  railway  tracks,  as  well  as  in  pond  margins 
and  in  marshes,  but  they  do  not  commonly  occur  in  peat-bogs 
or  tamarack  swamps,  except  at  the  edges. 

Related  to  the  water-plantains  are  the  arrowheads,  plants  of 
similar  habitats  and  generally  to  be  distinguished  by  their  broad 
leaves,  shaped  like  spear-heads.  The  arrowheads,  like  the 
pondw7eeds,  frequently  put  forth  two  kinds  of  leaves,  and  if  a 


2O2 


Minnesota  Plant  Life, 


FIG 


Arrowhead.     After    Britton 
and  Brown. 


plant  is  pulled  up  by  the  roots  it  will  be  discovered  very  possibly 

that  there  are  broad  or  slender  grass-like  leaves  submerged  in 

the  water.  In  one  Minnesota  va- 
riety the  arrow-headed  leaves  float 

upon  the  surface  of  the  water  like 

those  of  the  pond-lilies,  but  more 

commonly  they  are  not  natant.     In 

some  species  all  of  the  leaves  are 

grass-like    or     slender,    while    the 

plants  must  be  recognized  rather  by 

their  characteristic  flowers.    A  large 

number  of  separate  carpels  are  pro- 
duced in  each  flower  and  when  it 

ripens  the  group  of  carpels  become 

a  more  or  less  spherical  head.     In 

each  of  the  closed  carpels  or  ovaries 

is  a  single  erect  seed  slightly  curved. 

In  Minnesota  there  are  at  least  six  species  of  arrowheads. 

Eel-grasses.  A  fifth  fam- 
ily in  this  second  order  in- 
cludes the  well-known  eel- 
grass,  the  plant  which  gives 
so  delicate  a  flavor  to  the 
flesh  of  the  canvas-back 
duck,  which  is  very  fond  of 
pulling  it  and  eating  the 
soft  parts  of  the  leaves  and 
stems.  There  is  something 
very  remarkable  about  the 
way  in  which  this  plant  pro- 
duces its  flowers.  The  gen- 
eral plant-body  consists  of  a 
(short  stem  rooted  in  the 
mud  on  the  bottoms  of  lakes 
near  their  edges.  The  leaves 

FIG.  81.    Eel-grass.    After  Britton  and  Brown.      are  long,  graSS-Hke  and  of  a 

diaphanous  translucent  green,  rarely  floating  at  the  surface, 
more  generally  submerged  and  ascending.  The  pistillate  flow- 
ers are  produced  at  the  end  of  a  very  long,  slender  spiral  stem 


Minnesota  Plant  Life,  203 

which  rises  in  sinuous  coils  through  the  water,  bringing  the 
flower  just  to  the  surface.  The  staminate  flowers  are  in  clus- 
ters on  a  short  stem  deep  down  in  the  water.  When  they  are 
nearly  ripe  they  separate  from  the  stem  and  rise  to  the  surface, 
where  they  open,  revert  their  perianth  leaves  and  are  free  to  be 
blown  about  on  the  quiet  surface  of  the  pool  like  so  many  min- 
iature boats.  Some  of  them  thus  approach  the  pistillate  flowers 
and  the  pollen-spores  can  fall  upon  the  stigmas  where  they  ger- 
minate. After  pollination  the  long,  coiled  stem  contracts  and 
pulls  the  pistillate  flower  down  into  the  depths  where  it  may 
ripen  its  fruit  in  safety.  The  fruit  itself  is  a  cylindrical  capsule 
with  numerous  seeds. 

In  near  affinity  to  the  eel-grass  is  a  little  plant  which  is  some- 
times called  ditch  moss  or  water  weed  and  is  known  by  its  short 
leaves  of  a  crisp  texture  when  taken  from  the  water.  The  leaves 
are  opposite,  rather  close  together  and  commonly  not  more  than 
half  to  three-quarters  of  an  inch  in  length.  Their  points  are 
often  turned  back  so  that  a  characteristic  appearance  is  given 
to  a  branch. 


Chapter  XXIII. 

Grasses  and  Sedges* 


The  third  order  is  not  represented  in  Minnesota,  but  the 
fourth  order,  which  includes  the  grasses  and  sedges,  is  abun- 
dantly represented  by  a  large  variety  of  forms.  There  are  in 
the  state  about  160  different  species  of  grass  and  about  the  same 
number  of  sedges. 

Grasses.    Grasses  are  characterized  by  their  habit  of  forming 

the  sort  of  fruit  which  is 
termed  a  grain.  They  are,  in 
Minnesota,  all  of  them  annual 
or  perennial  herbs,  but  in  In- 
dia and  the  Orient  some  va- 
rieties become  large  trees,  in 
which  condition  they  are 
termed  bamboos.  The  stems 
are  for  the  most  part  hollow, 
the  leaves  slender  and  sheath- 
ing, though  some  panic  grass- 

FIG.  82.    Wild  rice  and  pond  lilies.     After 

photograph  by  Williams.  CS  have   broad   leaves Ol"   CVCU 

ovate  leaves  in  certain  foreign 

species.  The  flower  clusters  are  generally  spikes  composed  of 
little  spikes  known  as  spikclets.  In  the  flower  clusters  and 
flowers,  the  leaves  are  developed  as  chaffy  scales  and  the  flowers 
themselves  lack  any  colored  perianth.  There  are  usually  three 
stamens  and  the  ovary  has  but  one  cavity  producing  but  a  single 
seed.  The  ovary  is  conceived  to  consist  of  one  carpel,  the  other 
two  having  disappeared.  The  branched  stigma  on  top  of  the 
rudimentary  fruit  is  feather-like,  and  for  its  pollination  the  chief 
agent  is  the  wind.  The  ripened  fruit  inclosed  in  its  chaffy 
scales  is  called  a  grain.  The  seed  inside  the  grain  is  not  sep- 
arate but  fills  up  the  fruit-cavity  so  that  the  whole  is  one  solid 


Minnesota  Plant  Life. 


205 


FIG.  83.    Beard-grass.    After  Britton  and 
Brown. 


body.     There  is  always  albumen  in  the  seed  and  the  embryo 

lies  toward  one  side,  nursing  on  the  albumen  by  its  peculiar 

sucker-shaped      seed-leaf.     This 

may  be  seen  when  one  carefully 

removes    the    embryo    or    germ 

from    a    corn    fruit    or    from    a 

wheat    kernel.     It  will    then  be 

noticed  that  the  embryo  has  on 

one  side  a  flattened  disc  which 

presses   itself   against    the   albu- 
men, and  by  it  the  plantlet  nurses 

as  the  seed  begins  to  germinate. 
There    are    several     tribes    of 

grasses  recognized :    the  maizes, 

to   which   Indian   corn   belongs; 

the  bluejoints,  including  also  the 

sugar-cane ;     the    panic-grasses, 

with  which  the  barnyard  grass, 

the  sand-burrs  and  their  allies  are 

grouped ;  the  rices,  of  which  the  Minnesota  representative  is  the 

well-known  wild  rice  or  Indian  rice;   the  canary-seed  grasses; 

the  timothies  and  millets,  in- 
cluding also  some  sand-bind- 
ing grasses  and  tumbling- 
grasses;  the  oats,  comprising 
the  well-known  wild  oats  and 
a  number  of  kindred  genera; 
the  fescue  grasses,  with  blue- 
grass  and  reed-grass  as  types; 
the  buffalo-grasses,  and  the 
barleys  with  which  tribe  are 
also  grouped  both  wheat  and 
rye.  Only  two  of  the  large 
tribes  of  grasses  are  unrepre- 
sented in  Minnesota  by  native 
varieties.  These  are  the  maizes 
and  the  bamboos;  but  Indian 
corn,  one  of  the  maizes,  is  so 

abundantly  cultivated  that  it  may  rightfully  be  regarded  as  a 
Minnesota  plant. 


FIG.  84.     Barnyard  grass.     After  Britton  and 
Brown. 


206 


Minnesota  Plant  Life, 


FIG.  85.     Minnesota  Muhlenberg  grass. 
After  Britton  and  Brown. 


Varieties  of  grasses.  It  is  not  possible  in  the  space  at  com- 
mand to  give  any  adequate  idea  of 
the  various  species  of  grasses  which 
grow  within  the  borders  of  the 
state.  The  majority  of  them  are 
turf-forming  plants  and  are  marked 
by  strong  underground  rootstocks 
which  branch  and  creep  beneath  the 
surface  of  the  soil,  sending  lateral 
offshoots  into  the  light.  A  great 
many  different  types  of  flower  clus- 
ters are  to  be  met  with,  varying 
from  the  solid  spikes  of  the  timothy 
or  millet  to  the  very  loose  and 
straggling  clusters  of  the  tumble- 
grasses  and  blue-grasses.  A  few 
grasses  are  aquatic,  permitting  their 

leaves  to  float  on  the  surface  of    the  water.     These  may  be 
recognized,  when  in  flower  or  in  fruit,  by  the  characteristic 

grass-like  aggregates  which  they 
produce.  Some  are  semi-aquatic, 
finding  their  homes  on  the  edges 
of  lakes  or  swamps,  as,  for  ex- 
ample, the  reed-grasses  and  the 
wild  rice.  A  number  of  varieties 
are  found  only  in  tamarack 
swamps  and  marshes  or  where 
there  is  an  abundance  of  shade. 
A  few,  with  sparsely  clustered 
flowers  and  rather  broad,  thin 
leaves,  frequent  the  depths  of  the 
forest,  but  the  great  majority  are 
to  be  looked  for  in  meadows  and 
on  the  prairie.  Some  of  them,  like 
the  buffalo  grass,  with  their  shriv- 
eled aspect  and  vigorous  root- 
system,  indicate  a  strong  adap- 
tation to  dry  regions  or  deserts. 

Indian  corn.     Sometimes  in  the  grasses  the  flowers  are  sep- 
arated so  that  the  staminate  flowers  occur  in  different  clusters 


FIG.   86.     Beckman    grass.      After  Britto 
and  Brown. 


Minnesota  Plant  Life. 


207 


from  the  pistillate,  just  as  in  the  cat-tails.  It  is  so  with  the 
Indian  corn,  where  all  the  staminate  flowers  normally  develop 
in  the  area  known  as  the  tassel,  where  all  the  pistillate  flowers  are 
gathered  together  on  a  thick  stem  and  form  the  ear.  In  the 
Indian  corn  the  process  which  connects  the  stigma  with  the 
ovary  is  long  and  slender  and  is  known  as  the  silk.  Surround- 
ing the  cluster  of  pistillate  flowers  on  their  thick  stem  or  cob 
is  a  group  of  somewhat  modified  protective  leaves  known  as  the 
husks  of  the  corn.  Since  the  plant  depends  upon  the  wind 
for  carrying  the  pollen-spores  to  the  stigma,  the  silk  threads 
protrude  in  a 
little  tuft  at  the 
end  of  the  ear. 
By  selectin  g 
ears  which  have 
not  yet  opened 
to  expose  their 
silk  and  inclos- 
ing them  in  a 
gutta-p  e  r  c  h  a 
bag  it  would  be 
possible  to  pre- 
vent the  devel- 
opment of  the 
kernels. 

A  number  of 
cultivated  vari- 
eties of  Indian  corn  are  recognized,  differing  in  minor  peculiar- 
ities. Hybrids  between  different  varieties  are  interesting  and 
sometimes  red  and  white  corn  are  crossed ;  in  that  instance  tinted 
kernels  may  develop  upon  the  cob.  Or  if  red,  white  and  black 
varieties  are  grown  together  in  the  same  field  some  kernels  may 
be  fecundated  by  male  plants  arising  from  one  kind  of  pollen 
while  others  depend  upon  males  developed  from  other  pollen, 
so  that  the  ears  contain  kernels  of  each  color. 

Wild  rice.  Another  grass  which  is  of  interest  from  its  im- 
portance as  an  economic  plant  among  the  aborigines  of  the 
state,  is  the  wild  rice  or  Indian  rice.  The  Chippewas  call  this 
plant  manotnin  and  gather  it  in  the  autumn  of  the  year  for  food. 


FIG.  87.     Indian  corn  in  the  shock.     After  photograph  by  Williams. 


208 


Minnesota  Plant  Life. 


It  occurs  in  large  quantities,  especially  in  narrows  between  lakes, 
in  outlets  or  inlets,  but  not  so  commonly  in  bays  or  stagnant 
water.  It  is  not  so  frequent  in  lakes  without  an  outlet.  The 


FIG.  88.    Wild  rice  in  a  Minnesota  lake.     After  photograph  by  Williams. 

grain  is  longer  and  thinner  than  the  rice  of  the  orient,  but  when 
boiled  is  quite  as  agreeable  to  the  taste  as  the  cultivated  form. 
The  Indians  collect  it  in  September,  beating  it  into  their  canoes, 


Minnesota  Plant  Life. 


209 


FIG 


Wild  rice.    After  Britton  and 
Brown. 


and  after  harvesting  it  is  winnowed  by  hand.  Under  the  crude 
manipulation  of  the  Indian  much  chaff  is  usually  left  with 
the  grain,  so  that  the  wild  rice 
cake  or  porridge  which  the  In- 
dian makes  is  not  always  so  ap- 
petizing as  one  might  desire. 
The  wild  rice,  when  it  flowers, 
behaves  somewhat  like  Indian 
corn,  but  both  varieties  of  flower- 
clusters  are  rather  broad  panicles. 
The  spikelets  contain  one  flower 
each  and  the  pistillate  spikes  are 
borne  higher  on  the  stem  than 
the  staminate,  thus  reversing  the 
relative  position  in  the  Indian 
corn.  Each  staminate  flower  con- 
tains six  stamens.  The  pistillate 
flower  consists  of  a  single  ovary 
with  two  divergent  feathery  stig- 
mas. 

Wheat.  More  important  to  man  than  any  other  grasses  in  Min- 
nesota are  the  wheats,  which  form  the  principal  agricultural  prod- 
uct of  the  state.  In  the  wheat  the 
flowers  are  perfect,  not  separated 
as  in  the  corn  or  wild  rice.  Sur- 
rounded by  its  own  cluster  of 
stamens  each  pistil  is  normally 
sure  of  pollination.  When  the 
fruit  develops  it  forms  an  ovoid 
grain  with  the  embryo  basally 
and  laterally  disposed.  A  large 
number  of  varieties  of  cultivated 
wheat  are  known,  the  hybridiza- 
tion and  selection  of  which  are  of 
the  utmost  importance  to  the 
agriculture  of  the  future,  since  by 
such  intelligent  methods  will  it 
eventually  be  possible  to  produce 

varieties  which  are  rust-proof  and  far  richer  in  flour-making  sub- 
stances than  are  the  wheats  of  to-day. 
15 


FIG.  90.    Kalm's  brome-grass.    After 
Britton  and  Brown. 


210 


Minnesota  Plant  Life. 


Distribution  of  grass  grains.  A  few  grasses  in  the  state 
have  interesting  special  methods  of  distributing  their  fruits. 
The  sand-bur,  for  example,  encloses  its  fruits  in  bur-like  scales. 
If  carefully  examined,  the  points  on  the  burs  will  be  found  to 
have  barbs  directed  backwards  along  their  sides,  so  that  a  bur 
sticks  very  closely  to  the  fur  of  an  animal  or  to  clothing  and 

thus  brings  about  the  dissemina- 
tion  of    the  fruits  within.     An- 
other grass  known  as  spear-grass, 
or  to  children  as  "fairy's  spears," 
is    remarkable    for    the    "self- 
planting  attachment"   of  the 
grain.     In  this  variety  the  grain 
is  enclosed  in  a  chaffy  scale,  the 
end  of  which  is  prolonged  into  a 
slender  awn,   while  the  base  is 
sharply  pointed,  hard,  and  pos- 
sessed   of    hairs    pointing    back- 
wards.    When   such    grains   fall 
upon  the  soil  the  tips  penetrate 
a  little,  owing  to  the  heaviness 
iof  the  seed.  The 
slender    bristle 
then  begins  to 
coil  and  uncoil 
under  the  stim- 
ulus given  to  it 
by    changes   in 
the  moisture  of 
the  air.      Since 
the  grain  holds 
all  the  ground 
that  it  gains  on 


FIG.  91.  A  cluster  of  sedge-flowers  (Carex-type),  a  single 
pistillate  flower  with  one  fruit  rudiment,  and  a  stami- 
nate  flower  with  three  stamens.  After  Atkinson. 


account  of  its  backward-pointing  hairs  it  is  slowly  driven  into 
the  soil  and  thus  enjovs  a  certain  advantage  over  varieties 
which  have  not  such  self-planting  mechanism.  Grasses  are  not 
alone  in  apparatus  of  this  sort,  for  the  fruits  of  the  clematis  and 
of  some  geraniums  are  similar  to  a  degree.  Other  species  of 
grass  are  provided,  upon  their  fruits,  with  expansions  or  tufts 
of  cottony  hairs,  by  which  the  wind  assists  them  in  their  dis- 


Minnesota  Plant  Life. 


21  I 


tribtition,  while  tumbling  grasses — after  they  have  ripened  their 
seeds — separate  their  flower-clusters,  bring  them  together  into 
balls  and  permit  the  wind  to  roll  them  over  the  plains  or 
meadows. 

Mat-grasses  and  dune-grasses.  A  few  grasses  take  the  form 
of  what  are  known  as  mat-plants  or  carpet-plants.  These  are 
found  in  waste  fields  and  the  plant-body  has  a  marked  prostrate 
appearance,  lying  flat  upon  the  ground  and  producing,  if  unin- 
terfered  with,  a  circular  disc  a  foot  or  more  in  diameter.  Such 
vegetation-forms  could  not  very  well  arise  in  the  forests  or  in 
marshes,  but  are  charac- 
teristic of  open,  sandy 
fields.  Peculiar  varieties 
of  grasses  are  usually 
found  on  sand-d  u  n  e  s  . 
These,  of  which  the  wild 
rye  is  a  conspicuous  ex- 
ample, have  a  luxuriant 
subterranean  body  made 
up  of  rootstocks  and 
roots  by  which  they  bind 
the  sand  together — hence 
they  are  known  as  sand- 
binding  grasses.  The 
planting  of  grasses  of  this 
sort  where  sand-dunes 
show  a  tendency  to  en- 
croach inland,  is  Often  FIG.  92.  Cyperus-sedge.  After  Britton  and  Brown. 

sufficient  to  stay  the  ad- 
vance of  the  dune.  In  France  such  grass-planting  is  employed 
by  the  inhabitants  along  the  coasts  of  Brittany  to  prevent  the 
beach  sand  from  being  blown  continuously  in  shore.  In  north- 
ern Indiana,  between  Chicago  and  Elkhart,  there  is  an  area 
where  the  sand  of  Lake  Michigan  has  been  blown  inland  for 
many  miles,  covering  the  soil  and  by  its  thick  drifts  making  val- 
uable farms  worthless.  In  such  positions  considerable  growths 
of  wild  rye  would  serve  to  bind  the  sand  and  raise  a  barrier  to 
its  farther  encroachment. 


212 


Minnesota  Plant  Life. 


Sedges.  The  sedges  are  a  family  of  plants  closely  akin  to 
the  grasses  and  with  them  constituting  the  fourth  order.  They 
are  mostly  grass-like  in  appearance,  though  some,  like  the  bul- 
rushes, are  singular  in  aspect  owing  to  their  special  habitats. 
As  compared  with  the  grasses  they  present  some  differences 
which  may  be  kept  in  mind  and  should  enable  one  to  distin- 
guish the  two  families  at  a  glance.  The  stems  are  slender,  gen- 
erally solid,  instead  of  hollow  as  in  almost  all  the  grasses.  Very 
often  the  sedge  stem  is  triangular  or  quadrangular,  a  character 


FIG.  93.     Cotton-grasses  growing  in  a  bed  of  peat-moss.     Near  Grand  Rapids.     After  photo- 
graph by  Mr.  Warren  Pendergast. 

not  at  all  common  among  grasses.  Some  sedges,  however,  like 
grasses,  have  cylindrical  stems.  The  leaves  are,  when  present, 
altogether  grass-like.  The  flowers  resemble  those  of  grasses, 
except  that  the  number  of  stamens  is  rarely  more  than  three. 
The  ovary  is  one-chambered,  develops  a  single  seed  and  in  gen- 
eral resembles  the  ovary  of  the  grass.  The  stigma  is  often 
three-cleft  but  sometimes  simple  or  two-cleft.  The  fruit  is 
ordinarily  a  three-cornered  nutlet  with  mealy  albumen  and  minute 
embryo. 


Minnesota  Plant  Life. 


213 


Cyperus-sedges.  Here  are  included  the  Cyperus  plants.  To 
this  genus  the  familiar  umbrella-plants  of  window  gardeners 
belong  and  here,  too,  is  to  be  placed  the  papyrus  of  Egypt, 
famous  in  ancient  days  as  a  substitute  for  paper.  The  papyrus 
stems  were  pounded  out  into  flat  plates  which,  matted  together, 
furnished  the  papyrus  rolls  upon  which  so  many  ancient  manu- 
scripts are  written.  In  Minnesota  the  Cyperus  sedges  are  found 
principally  along  the  muddy  borders  of  ponds  and  streams,  in 
marshes,  ditches  and  wet  places.  In  many  of  them  the  stem  is 
triangular  with  most  of  the  leaves  clustered  at  the  base.  The 
spikes  are  often  borne  in  the  kind  of  cluster  known  as  an  umbel, 


FIG.  94.    L,ake  border  vegetation.     Bulrushes  and  reed-grasses.    After  photograph  by 

Williams. 

of  which  the  parsley  family  furnishes  such  good  examples. 
Sometimes  these  umbels  are  loose  and  compound,  in  other  spe- 
cies they  are  compacted  into  almost  globose  heads,  while  in  still 
others  they  are  lax  and  simple. 

Cotton-grasses.  In  this  family  are  the  cotton-grasses,  such 
characteristic  plants  of  the  tamarack  swamps  and  peat-bogs  of 
the  state.  The  fruits  of  the  cotton-grasses  are  clothed  with 
white  bristles  growing  up  from  under  their  bases  so  that  the 
head  of  a  cotton-grass  looks  much  like  a  tuft  of  cotton  at  the 
end  of  a  slender  stem.  There  are  several  varieties  in  Minne- 
sota. 


214 


Minnesota  Plant  Life. 


Bulrushes.  Here  are  also  the  bulrushes  and  their  allies,  a 
number  of  which  are  natives  of  the  state.  The  most  common 
bulrush  is  the  one  that  forms  beds  at  the  margins  of  many 
Minnesota  ponds  and  lakes,  This  plant  has  stout  creeping 
rootstocks  which  branch  underneath  the  soil  of  the  bottom. 
Lateral  branches  of  the  main  stem  arise  into  the  air,  growing 
sometimes  from  seven  to  nine  feet  tall,  with  a  few  sheathing 
leaves  at  the  base  and  a  leaf  or  two  at  the  point  where  the  flower- 
cluster  branches  originate.  The  erect  stem  as  a  whole  is  a 
slender  green  cylinder,  whip-shaped  and  beautifully  constructed 
to  withstand  the  wind  and  surf  of  its  habitat.  The  bulrush  is 
an  example  of  a  small  adapta- 
tional  group  known  as  surf- 
plants.  The  leafless  character 
of  the  stem  may  be  regarded 
as  the  result  of  experience  in 
surfy  water,  for  in  such  a  posi- 
tion the  leaves,  if  they  had 
existed,  would  probably  have 
been  torn  away  and  the  plant 
has  therefore  learned  how  to 
exist  without  any  leaves  over 
the  principal  portion  of  its  sur- 
face. 

There  are  a  variety  of  rea- 
sons why  different  p  1  a  n  t  s 
abandon  their  leaves.  Some- 
times the  leafless  habit  is  an  adaptation  to  very  dry  atmospheres ; 
therefore  a  number  of  desert  plants  are  leafless,  because  if  they 
had  leaves  they  would  tend  to  transpire  moisture  more  rapidly 
than  they  could  absorb  it.  Again,  the  absence  of  leaves  may 
be  an  adaptation  to  strong  winds ;  thus  the  switch-plants  on  the 
islands  of  the  Adriatic  may  be  regarded  as  varieties  which  have 
abandoned  their  leaves  because  of  the  frequency  of  violent  blasts 
that  would  be  likely  to  tear  or  destroy  them.  In  the  bulrush, 
however,  the  leafless  habit  is  partly  a  response  to  the  prevalence 
of  surf  in  places  where  the  plant  is  accustomed  to  make  its 
home. 


FIG.  95.     Bulrush-sedge.     After  Brittou  and 
Brown. 


Minnesota  Plant  Life. 


2  I 


Many  bulrushes  have  three-cornered  stems  and  grow  in 
marshes  or  even  upon  prairies,  but  these  are  to  be  connected 
with  the  ordinary  cylindrical  bulrush  of  lakeshores  because 
of  the  exact  similarity  of  their  flowers  and  fruits.  Indeed,  the 
three-cornered  stem  was  probably  primitive  and  the  cylindrical, 
adaptational. 

Carex-sedges.  The  largest  genus  of  plants  in  Minnesota 
— after  the  rusts — belongs  to  the  sedge  family,  and  there  are 
about  no  species  of  Car  ex  in  the  state.  The  Carices  are  grass- 
like  sedges,  for  the  most  part  small  and  slender  plants  and  per- 
ennial by  underground  rootstocks.  Each  pistillate  flower  de- 
velops a  sac-shaped  leaf  which 
incloses  the  rudimentary  fruit, 
so  that  when  ripe  it  stands  in 
a  little  bladder,  reminding  one 
somewhat  of  the  ground- 
cherry,  only  very  much  smaller. 
These  sacs  may  be  either  pa- 
pery or  hard  and  they  may  be 
either  smooth,  furrowed  or 
winged.  Usually  the  stigmas 
are  protruded  far  beyond  the 
top  of  the  sac  which  itself  takes 
the  form  of  a  bottle,  and 
through  the  neck  of  this  the 
stigmas  are  thrust.  Some- 
times the  stigma  is  two-lobed, 
while  in  other  species  the  number  of  the  lobes  is  three.  A  con- 
siderable variety  exists  in  the  shape  of  the  sac  in  which  the  fruit 
is  formed.  Sometimes  it  is  slender,  while  again  it  is  swollen 
or  even  globose.  In  many  sedges  the  pistillate  flowers — their 
fruit-rudiments  inclosed  in  the  sacs — are  displayed  in  special 
spikes  or  heads,  while  the  staminate  flowers  stand  in  other  spikes 
above  or  below  the  pistillate — if  the  two  occur  on  the  same 
general  axis — or  entirely  separate  from  them.  Among  the 
Carices  the  flower  clusters,  in  their  general  shape  and  in  their 
position  on  the  plant-body,  show  great  variety.  Sometimes 
they  are  cylindrical  and  pendulous,  again  cylindrical  and  erect 
or  ascending,  again  globose  or  loosely  aggregated.  In  still 


FIG. 


Carex-sedge.    After  Britton   and 
Brown. 


216  Minnesota  Plant  Life. 

other  instances  they  form  long  clustered  groups  made  up  of 
numerous  spikes  of  flowers.  One  of  these  little  sedges  is  an 
extremely  common  flower  of  early  spring,  dotting  the  prairies 
with  its  little  yellow  spikes  of  staminate  flowers  below  which 
whitish  spikes  of  pistillate  flowers  are  formed.  The  yellow  color 
is  given  by  the  stamens  themselves. 

Some  of  the  sedges  are  robust,  strong  plants,  almost  like  bul- 
rushes in  their  general  aspect,  while  others  are  very  delicate, 
low-tufted  plants,  bringing  to  mind  the  smaller  sorts  of  grasses. 
In  the  classification  of  this  large  genus  of  plants  a  variety  of 
characters  are  taken  into  consideration — the  number  and  posi- 
tion of  the  flowers,  the  character  of  the  sac  which  incloses  the 
fruit,  the  distribution,  shape  and  color  of  the  scales,  the  width, 
length  and  texture  of  the  leaves,  the  number  of  branches  of  the 
stigma  and  the  general  distribution  of  the  flowering  tracts  upon 
the  axis  where  they  develop.  Economically,  sedges  are  by  no 
means  as  important  as  grasses;  neither  are  their  stems  so  val- 
uable as  fodder,  nor  do  their  fruits  serve  to  feed  mankind  as  do 
those  of  the  rice,  wheat,  rye  and  maize,  all  of  which  belong  to 
the  other  family  of  the  order.  Yet  a  considerable  industry  is 
being  developed  in  the  manufacture  of  matting  from  one  com- 
mon Minnesota  variety  and  the  plants  are  not  without  their 
uses. 


Chapter  XXIV. 

From  Callas  to  Water  Star-grasses. 
if 

The  fifth  and  sixth  orders — the  palms  and  cyclanthuses — 
are  not  represented  in  Minnesota,  but  the  two  families  of  the 
seventh  order  are,  by  a  few  well-marked  species.  Here  come  the 
plants  of  the  arum  family,  comprising  in  Minnesota  the  jacks-in- 
the-pulpit,  the  calla,  the  skunk-cabbage  and  the  sweet-flag. 
These  are  of  somewhat  different  habits  and  structure,  but  they 
agree  in  producing  their  flowers  upon  fleshy  spikes  subtended 
or  surrounded  by  peculiar  leaves  known  as  spathes.  The  com- 
mon jack-in-the-pulpit,  for  instance,  develops  such  a  fleshy 
spike  of  flowers  and  the  spathe  encircles  the  cluster  as  a  cu- 
rious hood.  The  spathe  in  the  calla  lily  of  greenhouses 
forms  a  white,  vase-like  chalice  beneath  the  fleshy  spike,  while 
in  the  skunk-cabbage  it  becomes  a  livid  purple  cowl  open  at 
one  side.  In  the  sweet-flag  the  spathe  is  prolonged  straight 
above  the  apparently  lateral  fleshy  spike  and  seems  like  a  con- 
tinuation of  the  flattened  stem.  In  most  of  these  plants  the 
rootstocks  are  commonly  short  and  solid  and  contain  a  very 
acrid  sap.  The  unpleasant  taste  of  the  Indian  turnip  is  given 
in  part  by  crystals  of  lime  oxalate  enclosed  in  certain  cells  of 
the  bulb. 

The  fruit  of  the  arums  is  a  berry.  In  the  jack-in-the-pulpit 
the  berries  are  scarlet  and  mature  in  the  autumn.  In  the 
sweet-flag  they  are  crowded  together  and  gelatinous — often 
failing  to  mature.  All  of  these  plants  have  special  peculiarities 
of  growth  that  would  be  interesting  to  follow  in  detail  and  a 
few  points  are  particularly  worthy  of  attention.  If  in  the  curi- 
ous flower  clusters  of  the  skunk-cabbage  a  thermometer  be  in- 
serted, and  after  fifteen  or  twenty  minutes  it  be  removed  and 
read,  it  will  be  found  that  the  temperature  may  be  from  five  to 
fifteen  degrees  higher  than  that  of  the  surrounding  air,  showing 


2l8 


Minnesota  Plant  Life. 


the  power  of  the  purple  substances  in  the  spathe,  together  with 
the  respiratory  activity  of  the  fleshy  spike,  to  increase  the  tem- 
perature. In  the  jack-in- 
the-pulpit  flower  the  pecu- 
liar little  club-shaped  sterile 
end  of  the  spike  is  probably 
a  respiratory  organ  and  to- 
gether with  the  special  col- 
oring substances  does  its 
part  in  raising  the  tempera- 
ture. Small  insects  learn 
that  these  flower  clusters 
offer  them  comfortable 
shelter  and  seek  them,  and 
as  a  result  pollination  is  se- 
cured. The  flowers  of  most 
of  the  arums  depend  upon 
this  ability  to  furnish  heat 
rather  than  upon  perfumes, 
gaudy  colors  or  the  secre- 
tion of  nectar  to  attract 
their  insect  visitors. 

Burrowing  bulbs.  An- 
other curious  feature  in  the 
lives  of  many  arums  is  the 
burrowing  habit  of  the 
young  bulbs.  If  a  flower 
pot  about  six  inches  tall  is 
filled  with  rich  loam  and 
some  seeds  of  the  skunk- 
cabbage  or  jack-in-the-pul- 
pit  are  planted  about  half 
an  inch  below  the  surface 
and  permitted  to  germinate, 
the  plantlets  when  they 
burst  forth  will  at  once  be- 
gin the  formation  of  bulbs 
by  expanding  the  lower 
portions  of  their  stems  into 


FIG.  97.  A  skunk-cabbage  in  early  spring,  be- 
fore the  leaves  have  unfolded.  The  purple 
hood  covering  the  flower  cluster  is  shown  on 
one  side.  After  Atkinson. 


Minnesota  Plant  Life.  219 

round  and  solid  bodies.  In  a  week  or  so  after  such  a  bulb  has 
been  formed,  if  sought  where  it  first  appeared,  it  cannot  be 
found,  for  by  this  time  it  will  have  burrowed  to  the  bottom  of 
the  pot.  In  this  manner  the  erect  rootstocks  of  skunk-cab- 
bages sink  a  foot  or  two  into  the  soil — as  any  one  who  attempts 
to  dig  up  a  perfect  plant  will  soon  discover.  The  way  that  this 
is  accomplished  is  by  the  development  of  contractile  roots  on 
the  young  nodes.  Four  or  five  of  these  roots  are  sent  obliquely 
down  into  the  soil  on  different  sides  of  the  stem.  When  they 
are  long  enough  they  produce  some  short  lateral  branches  near 
their  tips,  thus  anchoring  themselves.  They  then  contract  and 
the  bulb  or  stem — the  base  of  which  may  be  sharply  pointed — 
is  pulled  down  into  the  earth.  By  this  means  the  plant  estab- 
lishes its  stems  sometimes  twenty  inches  below  the  point  where 
they  began  to  form.  The  contractile  roots,  differing  consid- 
erably from  the  ordinary  absorptive  roots,  may  be  recognized 
by  their  large  size  and  by  the  wrinkles  on  their  surface. 

Although  the  berries  of  most  of  the  arums  are  exceedingly 
unpleasant  to  the  taste,  some  birds  seem  to  fancy  them  and  their 
bright  red  color  in  the  jack-in-the-pulpit,  calla  and  skunk-cab- 
bage is  no  doubt  in  the  nature  of  an  advertisement  to  attract 
the  attention  of  such  as  will  eat  them. 

All  of  these  plants  except  the  sweet-flag  grow  in  rich  soil,  in 
deep  woods,  ravines  or  swamp  borders.  Like  most  shade- 
loving  plants,  they  have  large  leaves  of  thin  texture.  The  jack- 
in-the-pulpit  is  a  typical  shade  plant  in  structure.  Unlike  most 
of  its  class,  its  leaves  are  netted  veined  and  the  broad,  thin  blades 
are  fitted  to  catch  as  much  sunlight  as  possible.  The  flowers 
in  this  plant  are  commonly  of  two  kinds.  The  staminate  may 
occur  either  upon  the  same  fleshy  axis  with  the  pistillate,  and 
just  above  them,  or  upon  a  separate  axis.  The  peculiar  club- 
shaped  elongation  of  the  flowering  axis  in  the  jack-in-the-pulpit 
is  not  characteristic  of  the  calla,  the  skunk  cabbage  or  the  sweet 
flag,  for  in  the  latter  plants  the  flowers  cover  the  axes  to  their 
tips.  The  sweet-flag  occupies  a  different  habitat  from  the  oth- 
ers preferring  the  edges  of  streams  and  swamps.  Its  rootstocks 
are  used  in  pharmacy  and  are  often  collected  and  chewed  by 
children,  for  they  have  not  the  acrid  taste  and  are  harmless. 
The  leaves  of  the  sweet-flag  are  similar  to  those  of  the  blue  flag 


22O  Minnesota  Plant  Life. 

or  iris  and  quite  different  from  the  great  oval  leaves  of  the 
skunk-cabbage,  the  small  heart-shaped  leaves  of  the  calla,  or 
the  three-parted  leaves  of  the  jack-in-the-pulpit. 

Duckweeds.  The  duckweeds  are  small  natant  or  submerged 
plants  which  form  green  scums  on  pools  and  puddles.  They 
have  no  foliage-leaves  but  develop  little  flat,  oval  or  triangu- 
lar stems  which  float  upon  the  surface  of  the  water.  Some 
of  them  have  roots  which  hang  down  as  counterpoises,  but 
others  are  without  roots  and  appear  suspended  in  the  water  as 
tiny  green  ovoid  balls  not  as  large  as  a  pin-head.  The  latter 
are  the  smallest  of  all  flowering  plants  and  are  marvels  of  reduc- 
tion. When  the  duckweeds  flower,  which  they  very  seldom 
do,  the  stamen  and  pistil  stand  together  in  a  little  depression 
on  the  surface.  For  the  most  part  these  plants  depend  upon 
propagation  for  their  persistence  and  do  not  reproduce  by  seeds. 
In  Minnesota  there  are  five  or  six  species.  The  two  kinds  of 
duckweed  which  are  most  abundant  are  the  ivy-leaved  or  three- 
cornered  duckweed  and  the  smaller  duckweed.  In  the  latter 
the  floating  discs  are  about  an  eighth  of  an  inch  in  diameter 
and  of  nearly  circular  shape.  In  the  former  the  plant-body  is 
branched  more  abundantly  and  builds  up  a  group  of  three-cor- 
nered or  arrowhead-shaped  branches.  In  each  of  these  plants 
a  single  root  hangs  down  from  the  middle  of  the  plant-body. 

Another  somewhat  larger  duckweed,  with  discs  a  quarter  of 
an  inch  or  so  in  diameter  is  easily  distinguished  by  the  forma- 
tion of  tufts  of  roots  on  the  under  side.  In  these  plants  there 
are  traces  of  an  original  terrestrial  existence,  although  they 
have  become  so  much  modified  by  their  aquatic  life  that  they 
now  resemble  some  forms  of  algae.  Nevertheless  the  roots  in 
all  the  species  which  produce  these  organs  are  supplied  with 
root-caps,  structures  of  value  to  all  terrestrial  plants,  because 
they  protect  the  young  roots  as  they  penetrate  the  soil.  They 
are,  however,  of  no  value  to  aquatic  plants  and  some  aquatic 
plants  shed  their  root-caps.  The  little  floating  fern  of  Minne- 
sota is  interesting  from  its  general  habit  of  dispensing  with  the 
root-caps  shortly  after  the  roots  have  begun  to  extend  into  the 
water.  But  when  plants  like  the  floating  fern  or  the  duck- 
weed develop  roots  with  caps  and  afterwards  drop  these  caps, 
now  become  useless,  into  the  water,  it  may  be  assumed  that  they 


Minnesota  Plant  Life.  221 

are,  by  this  action,  indicating  their  original  terrestrial  habits 
and  proclaiming  as  distinctly  as  possible  that  they  were  not  al- 
ways floating  plants.  Of  the  duckweeds  the  one  most  per- 
fectly adapted  to  the  aquatic  habitat  is  at  the  same  time  the  most 
simple  of  all  flowering  plants.  One  must  carefully  distinguish 
between  that  simplicity  of  structure  which  is  rudimentary  and 
the  similar  simplicity  which  comes  from  reduction.  Low  types 
of  plants  like  some  of  the  algae  are  simple  in  form,  like  the 
smallest  duckweed,  but  their  simplicity  need  have  no  com- 
plexity behind  it.  Sometimes  these  tiniest  of  duckweeds,  mere 
little  green  specks  in  the  water,  lie  at  the  surface  and  produce 
each  on  its  upper  side  a  neat  little  stamen  and  pistil  quite  in  the 
style  of  their  earlier  terrestrial  days. 

The  eighth  order  includes  eleven  families,  of  which  but  four 
are  represented  in  Minnesota,  the  yellow-eyed  grasses,  the  pipe- 
worts,  the  spiderworts  and  the  pickerel-weeds. 

Yellow-eyed  grasses.  There  is  one  species  of  this  family  in 
Minnesota.  It  is  not  very  common  but  occurs  in  the  vicinity 
of  the  Twin  Cities.  The  general  appearance  of  the  plant  is 
grass-like  and  a  few  little  yellow  flowers,  each  with  three  dis- 
tinct petals,  are  formed  in  the  axils  of  a  group  of  scales  which 
stand  in  a  more  or  less  ovoid  head  at  the  tip  of  a  slender  erect 
stem.  The  most  favorable  place  to  seek  these  plants  is  near  the 
edges  of  a  tamarack  swamp  where  the  country  is  somewhat 
open,  or  on  banks  near  the  shores  of  lakes.  The  size  of  the 
plant  and  its  general  appearance  reminds  one  a  little  of  the 
blue-eyed  grass,  a  common  plant  of  the  iris  family,  but  the  color 
of  the  flowers  at  once  serves  to  distinguish  it. 

Pipeworts.  Related  to  the  plants  last  described  are  the  curi- 
ous little  forms  known  as  pipeworts,  of  which  a  single  species 
has  been  found  on  the  muddy  shores  of  some  Minnesota  lakes 
near  St.  Paul,  in  Chisago  county,  in  Douglas  county  and  in  Cass 
county — stations  indicating  a  wide  distribution  over  the  state. 
The  pipeworts  have  very  short  stems  on  which  little  tufts  of 
grass-like  leaves  are  borne.  From  the  centre  of  the  tuft  rises 
a  slender  stem  one  to  six  inches  in  height.  At  the  end  of  this 
is  formed  a  spherical  head  of  minute  flowers.  If  the  plant  grows 
beneath  the  surface  of  the  water,  as  it  often  does,  the  erect  stem 


222  Minnesota  Plant  Life. 

may  be  several  feet  in  length,  coming  up  like  a  wire  from  the 
bottom  of  the  pool  and  bearing  the  little  head  at  the  surface  of 
the  water.  The  name  pipewort  is  given  on  account  of  the  hol- 
low stem  which  bears  the  flowering  head. 

Blue-eyed-Marys.  The  spiderwort  family  includes  two  Min- 
nesota species,  the  common  spiderworts  or  blue-eyed-Marys 
frequent  on  banks,  along  roadsides  and  railway  tracks  and  at 
the  edges  of  meadows.  The  plants  are  mucilaginous  and  when 
broken  excrete  a  viscid  slime.  The  leaves  are  rather  thick, 
grass-like  in  form,  and  arise  from  a  simple  or  branched  stem. 
The  flowers  are  produced  in  generally  terminal  umbels  and  are 
of  a  bluish-purple  color  an  inch  or  so  in  diameter.  There  are 
three  purple  petals  and  three  green  calyx  leaves  below.  There 
are  three  carpels  fused  together  to  form  the  fruit  rudiment,  sur- 
rounded by  six  stamens.  When  the  ovoid  fruit  is  mature  it 
splits  by  three  longitudinal  lines  equi-distant  from  each  other, 
as  does  also  the  iris  fruit.  The  stamens  in  these  plants  possess 
tufts  of  interesting  purple  hairs  which  are  very  beautiful  objects 
for  microscopic  study. 

Pickerel-weeds.  A  somewhat  common  green-house  member 
of  the  pickerel-weed  family  is  known  as  the  water-hyacinth  and 
is  similar  in  its  flowering  clusters  to  the  rather  rare  native  pick- 
erel-weed of  Minnesota.  Any  one  who  has  seen  the  flowers  of 
the  water-hyacinth  will  recognize  the  pickerel-weed  if  he 
chances  upon  it  at  the  edges  of  a  marsh  or  in  tamarack  swamp. 
The  leaves  are  thick,  shaped  somewhat  like  those  of  the  arrow- 
head, and  arise  from  a  prostrate  rootstock.  The  flowering  stem 
stands  erect,  bearing  one  large  heart-shaped  leaf,  with  some 
sheathing  bracts  at  the  base.  The  whole  flowering  stem  varies 
from  one  to  four  feet  in  height,  while  the  large  leaf  may  be 
ordinarily  as  much  as  six  inches  long.  The  flowers  are  pale 
blue  and  delicate  in  texture  like  the  flowers  of  the  water-hya- 
cinth. They  occur  in  clusters  on  a  somewhat  fleshy  spike  at 
the  base  of  which  is  a  small  thin  spathe. 

Water  star-grasses.  Related  to  the  pickerel-weed  and  a 
member  of  its  family  is  a  little  mud-flat  plant  known  as  the 
water  star-grass.  When  growing  in  water  the  stem  of  this 
plant  is  two  or  three  feet  in  length,  no  thicker  than  a  knitting- 


Minnesota  Plant  Life.  223 

needle,  branching  frequently  and  possessing  short,  very  slender 
leaves  with  rather  sharp  points.  The  flowers  are  of  a  lemon- 
yellow  color  and  one  or  two  are  produced  at  a  time.  This  form 
is,  however,  rare  in  Minnesota  and  usually  the  water  star-grass 
appears  on  mud-flats  as  a  plant  two  or  three  inches  long  with 
characteristic  lemon-yellow  flowers,  each  with  six  equally  col- 
ored portions. 

To  this  order  belong  also  the  pineapples  and  Spanish  mosses 
of  the  south  and  several  tropical  families  not  represented  in  the 
United  States. 


Chapter  XXV. 

Rushes,  Lilies,  Blue  Flags  and  Orchids, 


The  ninth  order  includes  the  rushes,  the  lilies,  and  their  allies, 
the  bloodworts,  the  amaryllises,  the  yams,  and  the  blue  flags 
or  irises.     These  all  unite  in  the  general  character  of  the  flower 
which  is  made  up  of  the  six  portions  belonging  to  the  perianth, 
three  or  six  stamens  and  three  fused  carpels.     The  flower  of  the 
familiar  Easter  lily  is,  in  its  structure,  typical  of  the  whole  order. 
Rushes.    About  twenty  species  of  rushes  occur  in  Minne- 
sota.   They  are  for  the 
most     part     perennial 
grass-like  herbs,  com- 
mon upon  sand  beach- 
es,  in   prairie   sloughs 
and  back  a  little  way 
from    the    borders    of 
marshes     or    'swamps. 
The  flowers  are  ordi- 
narily    clustered     and 
are    characterized    by 
the  inconspicuous 
chaffy    appearance    of 
the  six  perianth  leaves. 
They  are  not,  however, 
subtended     by     scales 

and  arranged  in  spikelets  as  are  the  grass  and  sedge  flowers; 
and  rushes  need  not  be  mistaken  for  any  of  the  lower  families 
if  their  flowering  tracts  are  carefully  observed.  The  fruit  in 
rushes  is  a  small  capsule  which  splits  at  the  sides  like  the  much 
larger  fruit  of  the  iris.  The  seeds  vary  in  number  from  three 
to  several.  There  are  usually  three  or  six  stamens  in  each 
flower. 


FIG.  98.     Sedges  and  rushes.    After  photograph  by 
Williams. 


Minnesota  Plant  Life. 


225 


Two  genera  of  rushes, 
the  wood  rushes  and  the 
bog  rushes  are  found  in 
Minnesota.  The  wood 
rushes  are  recognized  by 
their  habitat  and  by  the 
position  of  the  bractlets 
beside  the  flowers.  The 
bog  rushes,  while  of  the 
same  general  appearance, 
commonly  produce  more 
seeds  in  each  capsule  than 
do  the  wood  rushes.  No 
little  variety  exists  among 
the  rushes  in  the  shape  of 
their  flower-c  lusters. 
Generally  they  are  rather 
flat-topped,  but  some  spe- 
cies exhibit  the  flowers  in 

globular    heads    and    Otll-     FIG.  99.     Dog's-tooth  violet  in  flower.     After  Atkinson. 

ers  in  loose  panicles. 

Lilies  and  their  allies.     About    forty  species  of    plants  be- 
longing to  the  lily  family  are  known  to  occur  in  Minnesota. 

Among  them  may  be  men- 
tioned the  trilliums,  or  wake- 
robins,  the  hellebores,  the 
asphodels,  the  bellworts,  the 
clintonias,  the  false  and  true 
Solomon's  seals,  the  asparagus, 
the  tiger-lilies,  the  dog's-tooth 
violets  and  the  wild  onions. 
These  plants  occupy  a  variety 
of  habitats.  Some,  like  the 
asphodels,  are  to  be  sought  in 
tamarack  swamps;  others,  like 
the  bellworts  and  Solomon's 
seals,  in  the  edges  of  the 
woods;  others,  like  the  clin- 

1'ic..  UK).     Clintonia.     After  Britton  and  Brown.    tOniaS      and      trilHlimS,     ill      the 
16 


226 


Minnesota  Plant  Life. 


depths  of  the  forest.  One  interesting  form,  known  as  alkali- 
grass,  grows  on  the  high  prairies  in  the  western  part  of  the  state. 
The  onions  are  found  in  six  different  varieties  and  are  best  de- 
veloped in  the  prairie  region  of  Minnesota,  but  they  occur  also 
in  the  forests. 

The  hellebore  is  notable  as  the  source  of  the  alkaloid  ver ci- 
trine, a  valuable  medicinal  compound.  The  bellworts,  of  which 
there  are  three  varieties,  are  common  and  attractive  flowers 
of  the  middle  spring.  The  onions,  with  their  characteristic 
bulbs,  smooth  in  some  species,  in  others  fibrous  or  reticulated; 
the  tiger  lilies  of  three  sorts  with  their  showy  flowers,  the  dog's- 
tooth  violets  of  three  varieties  with 
their  peculiarly  spotted  leaves  and 
white  or  yellow  flowers  are  all  familiar 
and  common  forms.  The  peculiar 
habit  of  the  Solomon's  seals  which 
separate  the  erect  stems  of  the  year 
from  the  strong  perennial  subterra- 
nean rootstocks  in  such  manner  as  to 
give  rise  to  circular  scars,  has  occa- 
sioned the  common  name.  Asparagus 
which  grows  wild  in  Minnesota  differs 
from  the  rest  of  the  family  in  being 
largely  devoid  of  leaves,  the  fine  green 
foliage  consisting  of  small  starch-mak- 
ing branches  rather  than  true  leaves. 
Smilax.  Among  the  lilies  may  be 
included  also  the  green  briars  or 
smilaxes,  noticeable  for  their  netted 

leaves  and,  in  most  varieties,  tendril-bearing  stems.  Five  spe- 
cies of  smilax  are  known  to  occur  in  Minnesota.  The  flowers 
in  these  plants  stand  in  umbels  and  the  fruits  mature  as  berries 
of  a  red  or  blue  color,  shading  towards  purple  or  black.  The 
stems,  which  twine  or  climb  upon  the  vegetation  near  them,, 
arise  from  large  swollen  underground  rootstocks.  One  variety 
of  smilax  common  in  Minnesota  is  quite  destitute  of  tendrils 
and  exists  as  an  erect  herb  a  foot  or  so  in  height.  Some  of  the 
smilaxes  are  very  bristly  with  prickles  upon  the  stems  or  edges 
of  the  leaves,  whik  others  are  smooth. 


FIG.  101.     Blue  flags.     After  pho- 
tograph by  Williams. 


Minnesota  Plant  Life. 


227 


Yams.  A  single  species  of  yam  is  common  in  woods  through- 
out the  southern  part  of  Minnesota.  The  body  of  the  plant  is 
herbaceous  or  slightly  woody.  Underground  rootstocks  are 
produced  from  which  slender  twining  vine-like  stems  arise, 
bearing  heart-shaped  broad  leaves  with  elongated  pointed  tips. 
The  flowers  are  small  and  borne  in  elongated  clusters.  When 
the  plant  fruits,  deeply  three-furrowed  papery  capsules  are 
formed  in  each  of  which  from  three  to  six  very  flat  thin  seeds 
are  enclosed.  The  rootstock  is  fleshy  and  some  of  the  tropical 
varieties  are  of  commercial  value  as  articles  of  food.  The  sweet 
potato,  sometimes  confused  with  the  yam,  is  an  entirely  differ- 
ent plant. 

Blue  flags. 
In  Minnesota 
the  iris  family 
includes  three 
species.  O  n  e, 
the  blue  flag  or 
iris  or  fleur-de- 
lis,  is  a  familiar 
object  in  swales 
and  mar  s  h  e  s 
and  is  common 
throughout  the 
state.  The 

large  blue  flowers  are  borne  on  erect  steins  with  leaves  similar 
in  appearance  to  those  of  the  cat-tail.  The  stems  arise  from 
woody  tuberous  rootstocks.  The  three-celled  ovary  matures 
into  a  capsular  fruit  in  which  the  seeds  are  very  much  flattened 
by  mutual  pressure. 

Blue-eyed  grasses.  The  other  plants  of  the  iris  family  are 
known  as  blue-eyed  grasses.  Of  these,  two  species,  by  some 
botanists  combined  into  one,  occur  in  Minnesota.  They  are 
but  diminutive  blue  flags,  being  tufted  grass-like  plants  with 
small  blue  flowers  about  a  quarter  of  an  inch  in  diameter.  They 
are  to  be  found  in  meadows  and  upon  wooded  slopes. 

Star-grasses.  One  species  of  star-grass  is  fairly  common  in 
the  southern  part  of  Minnesota.  In  general  appearance  it  is 
grass-like  with  a  swollen  solid  bulb  of  rather  oblong  shape 


FIG.  102.     Stream-side  vegetation.     Blue  flags  in  foreground. 
After  photograph  by  Williams. 


228  Minnesota  Plant  Life. 

and  usually  about  half  an  inch  in  diameter.  Upon  a  somewhat 
short  erect  stem,  generally  surpassed  in  length  by  the  leaves, 
are  borne  three  or  four  yellowish  flowers,  of  small  size,  in  a  flat 
topped  cluster.  This  plant  cannot  be  mistaken  for  the  yellow- 
eyed  grass  because  it  has  not  the  spherical  scaly  head  from  which 
originate  the  flowers  in  the  latter  variety. 

Besides  the  families  of  the  ninth  order  which  have  been  men- 
tioned there  are  four  others  not  represented  in  the  state.  Nor 
are  the  plants  of  the  tenth  order  found  so  far  beyond  the  tropics. 
It  is  to  this  order  that  the  bananas  and  the  zingibers,  the  cannas 
and  the  arrow-roots  belong.  Cannas,  however,  with  their  un- 
symmetrical  red  flowers  and  large  leaves  are  planted  for  orna- 
ment in  many  Minnesota  lawns  and  parks. 

Orchids.  The  eleventh  order  includes  but  two  families,  one 
of  which  is  not  found  in  Minnesota,  while  the  other,  the  orchid 
family,  presents  a  number  of  interesting  varieties.  Of  orchids 
there  are  about  45  species  in  the  state,  including  the  rein  orchids 
in  a  number  of  forms,  the  tress  orchids,  the  Arcthusas,  the 
Pogonias,  the  Calypsos,  the  coral-roots,  the  putty-roots,  and  the 
lady's  slippers  or  moccasin  flowers,  together  with  some  others. 
Orchids  differ  from  the  rest  of  their  class,  so  far  as  Minnesota 
is  concerned,  by  developing  flowers  with  bilateral  symmetry, 
while  the  flowers  of  lilies,  irises,  yams  and  the  rest  are  radially 
symmetrical  like  a  star-fish.  Orchid  flowers  have  a  distinct 
upper  and  under  side  like  snap-dragon  or  pea  flowers.  This  is 
probably  because  for  ages  they  have  stood  laterally  on  their 
stems  and  long  ago  in  response  to  this  habit  came  to  show  a  dif- 
ference between  the  side  toward  the  ground  and  the  side  toward 
the  skies.  Many  orchid  flowers  display  a  long  spur,  as  do  the 
larkspurs.  Others  produce  boat-shaped  or  slipper-shaped  bags 
as  does  the  moccasin  flower.  In  none  of  them  has  the  flower 
the  even,  radial  symmetry  possessed,  for  example,  by  the  tulip 
or  the  tiger  lily.  Not  only  for  the  presence  of  flowers  of  this 
type,  a  character  which  they  share  with  the  cannas  and  bananas, 
are  the  orchids  noted,  but  also  for  the  immense  number  of  very 
small  seeds  which  they  produce. 

In  numerous  orchid  flowers  a  peculiar  reduction  of  some  of 
the  stamens  takes  place,  so  that  in  many  of  them  there  remains 


Minnesota  Plant  Life. 


229 


but  a  single  functional  stamen  out  of  the  group,  the  others  be- 
ing reduced  to  mere  vestiges.  In  the  lady's  slipper,  however, 
two  stamens  of  the  group  remain  functional.  The  curious 
shapes  of  orchid  flowers  are  connected  with  insect  pollination 
and  the  orchid  flower  may  be  regarded  as  a  machine,  or  tread- 
mill, in  which  some  definite  species  of  insect,  different  for  the 
different  species  of  orchids,  is  temporarily  captured  and  forced 
to  work  for  the 
purposes  of  the 
flower. 

In  the  com- 
mon r  o  u  n  d  - 
leaved  orchid 
of  Minnesota, 
which  has  but  a 
single  stamen, 
if  a  pin  be  in- 
serted into  the 
spur  of  the 
flower,  passing 
along  a  groove 
between  the 
two  pollen- 
pouches  of  the 
stamen,  a 
couple  of  cir- 
cular adhesive 
discs  spring  out 

and  attach  themselves  to  each  side  of  the  pin.  On  each  of 
these  discs  is  a  stalk  at  the  end  of  which  a  mass  of  pollen- 
spores  is  collected.  The  two  little  masses  stand  up  like  dimin- 
utive Indian  clubs  for  an  instant  and  then  droop  forward. 
Here  one  sees  the  mechanism  designed  for  the  moth  that 
pollinates  the  flower.  When  the  insect  comes  to  the  plant  it 
finds  attractive  perhaps  only  one  flower  of  the  two  or  three 
which  are  finally  produced.  It  stands  in  a  definite  posi- 
tion, generally  upon  the  portion  of  the  flower  turned  toward 
the  ground,  and  introduces  its  bill  into  the  spur  where  a  little 


FIG.  103.     Yellow  lady-slipper.     After  photograph  by   Mr.   R.   S. 
Macintosh. 


230 


Minnesota  Plant  Life. 


honey  is  secreted.  In  order  to  obtain  the  honey  it  must  thrust 
its  bill  along  the  groove  where  the  two  adhesive  discs  are  sit- 
uated. When  the  insect  has  sipped  the  drop  of  honey  which 
it  seeks,  having  been  drawn  to  it  by  the  perfume  and  color  of 
the  flower,  it  flies  away,  carrying  with  it  the  two  pollen- 
masses,  one  on  each  side  of  its  bill.  Immediately  after  the 
insect  leaves  the  flower  the  two  pollen-masses  bend  forward 
and  the  next  flower  visited  receives  these  pollen-masses  fairly 
on  the  sticky  end  of  the  stigma,  where  the  pollen-spores  ger- 
minate and  give  rise  to  the  male  orchid  plants.  From  this  sec- 
ond flower  the  moth  carries 
away  a  fresh  pair  of  pollen- 
masses. 

Such  very  wonderful  and 
perfect  devices  secure  what  is 
termed  cross-pollination.  The 
pollen  is  taken  from  one  flower 
and  carried  to  the  stigma  of 
another  upon  another  plant, 
thus  apparently  insuring  a 
greater  vitality  and  breadth  of 
experience  in  the  embryo 
plantlets  which  are  to  be  de- 
veloped in  the  seeds.  A  va- 
riety of  such  mechanical  de- 
vices are  employed  by  plants. 
Those  of  the  orchids  with  their 

automatic  adhesive  discs  and  curving-stalked  pollen-masses  be- 
ing among  the  most  marvelous  in  their  perfection.  Yet  it  may 
be  said  that  the  orchids  are  over-refined  and  almost  too  per- 
fect. The  exactness  of  the  machine  is  indeed  so  great  that  the 
chances  against  its  working  are  apparently  infinitesimal.  The 
seeds,  however,  are  so  small  and  the  embryo  plantlets  are  pro- 
vided with  so  little  nutriment  with  which  to  enter  upon  their 
independent  life  that  the  great  majority  of  them  must  certainly 
perish.  The  orchids,  in  their  development,  have  given  their  at- 
tention, so  to  speak,  to  the  elaboration  of  highly  complicated 
methods  of  cross-pollination,  but  have  at  the  same  time  neg- 


FIG.  104.     Wild  orchis.     After  Britton  and 
Brown. 


Minnesota  Plant  Life.  231 

lected  the  proper  nutrition  of  the  plantlet  in  the  seed.  For  this 
reason  orchids  are  everywhere  rare  plants.  One  scarcely  ever 
finds  them  in  great  beds  such  as  those  in  which  many  other  sorts 
of  plants  habitually  occur,  and  possibly  their  infrequency  may 
be  attributed  to  the  failure  on  their  part  to  produce  sufficiently 
virile  seeds. 

The  habitat  of  Minnesota  orchids  is  somewhat  various.  The 
moccasin  flowers  which,  especially  in  their  fruiting  season,  are 
poisonous  to  the  touch  like  poison  ivy,  are  to  be  met  with 
in  tamarack  swamps  or  drier  localities  throughout  the  state. 
There  are  six  varieties  in  Minnesota,  differing  in  the  size,  shape 
and  color  of  the  flowers.  One  of  them,  the  yellow  moccasin, 
is  the  legal  "state  flower."  About  a  dozen  varieties  of  rein- 
orchids  may  be  found,  and  in  these  several  flowers  are  produced 
in  a  spicate  cluster.  The  flowers  in  some  of  the  rein-orchids 
are  fringed  like  those  of  the  fringed  gentians,  and  one,  with 
rather  large  purple  flowers,  is  not  uncommon  in  damp  places 
both  north  and  south.  Another  variety  with  fringed  petals  is 
found  in  tamarack  swamps.  In  this  the  flowers  are  greenish 
or  almost  white.  Still  another  type  of  orchid,  not  very  com- 
mon anywhere  except  in  the  woods  north  of  Lake  Superior,  is 
the  rattlesnake  plantain.  In  this  the  leaves  are  shaped  much 
like  those  of  the  common  plantain  and  are  curiously  mottled 
with  different  shades  of  green.  The  tress-orchids  are  delicate, 
slender  plants,  six  inches  or  so  in  height,  not  uncommon  in  pine 
woods  near  the  bases  of  old  stumps.  They  may  be  distin- 
guished from  the  other  orchids  by  their  somewhat  spirally 
twisted  spikes  of  flowers. 

Perhaps  the  most  ornamental  native  orchid,  when  seen  un- 
der favorable  conditions,  is  the  Calopogon  or  grass-pink.  This 
is  most  prettily  conspicuous  in  northern  peat-bogs,  where  it 
grows  among  the  cranberries  and  kalmias,  often  forming 
patches  of  considerable  size.  The  flowers  are  of  a  beautiful 
shade  of  purplish  pink  and  are  visible  for  some  distance  on 
account  of  their  brilliant  color. 

The  coral-roots  have  very  small  and  poorly  developed  leaves. 
They  are  humus  plants,  deriving  their  nutriment  to  a  large 
extent  through  the  cooperation  of  fungus  filaments  in  the  super- 
ficial layers  of  their  rootstocks,  and  the  singular  coral-like  ap- 


232  Minnesota  Plant  Life. 

pearance  of  the  infected  rootstocks  has  occasioned  the  popu- 
lar name  of  the  plant.  There  are  three  varieties,  rather  more 
common  in  northern  woods  than  in  the  southern  part  of  the 
state. 

In  several  of  the  orchids  bulbs  are  produced,  and  in  the  little 
putty-root,  not  very  rare  in  hard-wood  timber  where  the 
ground  is  covered  with  decaying  vegetable  mould,  the  bulb  is 
well-formed  and  about  the  size  of  one's  thumb. 

The  only  Minnesota  orchids  known  to  be  poisonous  to  the 
touch  are  the  lady's  slippers,  and,  especially  in  the  autumn,  it 
is  advisable  to  avoid  handling  these  plants.  The  leaves  and 
stems  are  furnished  with  two  kinds  of  hairs,  some  pointed  and 
apparently  harmless,  others  with  globular  tips  which  secrete 
small  quantities  of  oil.  Either  the  oil  itself  or  substances  in 
solution  may  irritate  the  skin,  and  careless  handling  of  a  plant 
is  frequently  the  beginning  of  much  discomfort.  In  the  early 
spring,  when  they  have  first  come  above  the  ground,  their  se- 
cretions do  not  seem  to  be  so  virulent.  The  seeds  of  the 
lady's  slipper  are  very  light  and  after  the  pods  containing  them 
have  opened  they  depend  upon  the  wind  for  distribution.  That 
the  plant  should  be  more  poisonous  while  the  seeds  are  matur- 
ing is  possibly  a  device  to  discourage  grazing  animals  from 
attacking  it  at  this  time. 


Chapter  XXVI. 

Poplars  and  Willows. 


There  have  now  been  passed  in  review  the  principal  Minne- 
sota types  of  higher  seed-plants  in  which  a  single  embryonal 
leaf  is  produced.  In  all  such  forms  the  first  leaf  springs  from 
the  tip  of  the  nascent  plant  in  the  seed,  and  the  rudiment  of  the 
stem  arises  as  a  lateral  protuberance  of  the  young  embryo. 

Plants  with  two-leaved  seedlings.  The  plants  included  in 
the  lower  class  are  not  so  numerous  as  the  species  which  be- 
long to  the  other  and  highest  group  of  the  vegetable  kingdom. 
The  latter  produce  a  pair  of  seed-leaves  by  bulgings  at  the  end 
of  the  young  spherical  embryo  shortly  after  it  has  begun  to 
form  from  the  fecundated  egg.  The  two  seed-leaves  are  devel- 
oped opposite  to  each  other  and  between  them  is  situated  the 
growing  point  of  the  stem,  so  that  when  seedlings  of  plants  of 
this  group  come  above  ground  they  may  generally  be  recog- 
nized by  the  pair  of  seed-leaves  between  which  the  little  bud 
of  the  stem  gradually  unfolds  itself.  There  are,  however,  some 
exceptional  cases  which  need  attention  before  passing  on.  In 
a  few  forms  the  growth  of  one  of  the  seed-leaves  is  at  a  very 
early  stage  arrested,  so  that  when  in  a  ripe  seed  the  plantlet  is 
observed  it  may  seem  to  have  but  a  single  seed-leaf.  This  is 
true  of  some  bladderworts.  Another  irregularity  is  to  be  no- 
ticed in  the  embryos  of  certain  parasitic  plants  like  the  mistletoe 
or  dodder.  In  these  the  seed  matures  without  the  develop- 
ment of  any  seed-leaves  whatever,  and  the  embryo,  upon  dis- 
section of  the  seed,  will  be  found  to  exist  as  a  tiny,  more  or 
less  spherical  body  near  one  end.  Here,  too,  it  may  be  recalled 
that  some  members  of  the  pine  family  produce  a  pair  of  seed- 
leaves,  yet  they  would  not  on  that  account  alone  be  included 
in  the  class  now  under  consideration.  In  all  instances  of  irreg- 
ularity it  is  conceived  that  special  influences  must  have  been 


234  Minnesota  Plant  Life. 

brought  to  bear  upon  the  embryo  plantlet  to  modify  it  from  the 
ordinary  type;  but  when  the  other  structures  of  the  plant  are 
taken  into  account  there  is  usually  no  difficulty  in  assigning  it 
to  its  proper  class. 

Stem  structure.  A  very  constant  character  of  plants  of  the 
highest  class  is  the  presence  in  the  stem  of  fibres  in  which  a 
longitudinal  layer  of  cells  remains  without  finally  maturing.  In 
trees,  the  seedlings  will  be  found  to  have  at  first  a  little  circle 
of  such  fibres,  which  by  mutual  pressure  upon  each  other  be- 
come blended  together  around  the  central  pith.  The  layer  of 
cells  known  as  the  cambium  in  each  of  the  fibres  thus  joins  with 
the  layer  of  a  fibre  next  to  it  and  a  cylinder  of  cambium  origi- 
nates, inclosing  the  young  wood  and  inclosed  by  the  young 
bark.  This  layer  of  cells  ordinarily  gives  rise,  during  every  year, 
to  new  wood  tissue  and  new  bark  tissue.  The  oldest  parts,  there- 
fore, of  a  tree-trunk,  are  the  outside  where  one  can  lay  one's 
hand,  and  the  heart-wood.  The  bark  is  younger  as  one  cuts 
from  the  outside  toward  the  wood,  but  the  wood  is  younger 
as  one  cuts  from  the  centre  toward  the  bark.  In  a  tree  there 
are  just  as  many  bark  rings  as  there  are  wood  rings,  but  the 
outer  bark  is  constantly  sloughing  off,  being  cracked  by  the  ex- 
pansion of  the  wood  within  and  by  exposure  to  the  disintegrat- 
ing effects  of  the  weather.  Besides  this,  the  ring  of  bark  that  is 
formed  by  the  cambium  during  a  year  is  commonly  not  so  thick 
as  the  ring  of  wood.  For  these  reasons  bark  may  be  only  an 
inch  or  more  thick,  while  the  wood  from  circumference  to  cen- 
tre may  measure  even  several  feet. 

Herbs  and  trees.  To  non-botanical  observers  it  is  sometimes 
difficult  to  explain  that  there  is  no  very  essential  difference  in 
structure  between  an  herb  and  a  tree,  providing  they  both  belong 
to  the  same  general  family  of  plants.  The  elm  is  so  very  much 
larger  than  the  nettles  which  grow  in  its  shade  that  upon 
any  one  who  considers  the  two  together  it  naturally  makes  a 
very  different  impression.  Yet,  nevertheless,  the  general  plan 
of  structure  in  the  two  is  very  similar.  In  the  nettle  there  is  a 
disposition  of  woody  tissue  inside,  with  bark  tissue  outside,  just 
as  in  the  elm,  but  the  tree  persists  possibly  for  hundreds  of  years, 
thickening  its  trunk  with  every  season,  while  the  stem  of  the 
nettle  dies  at  the  end  of  the  first  season  of  growth.  The  proper 


Minnesota  Plant  Life. 


235 


way  to  compare  trees  and  herbs  in  order  to  understand  their  sim- 
ilarity is  this:  Let  an  herb  be  pulled  up  by  the  roots  and  laid 
down  before  one.  Then  let  a  fresh  leaf-bearing  twig  of  a  tree, 
such  as  a  willow  or  poplar,  be  selected  and  removed  from  the  last 
year's  branch  upon  which  it  is  standing.  Let  one  of  the  young 
roots  of  the  tree,  if  it  is  found,  be  attached  to  the  end  of  the  twig 
that  was  broken  from  its  support.  Let  the  two  specimens  be 
placed  side  by  side  and  their  fundamental  resemblance  will  be- 
come apparent.  The  same  fact  will  be  understood  if  one  com- 


FIG.  105.     Cottonwoods  on  the  Minnesota.     After  photograph  by  Williams. 


In 


pares  the  seedlings  of  trees  with  the  seedlings  of  herbs, 
essential  respects  they  will  appear  altogether  similar. 

Other  characters  of  plants  with  two-leafed  seedlings.  The 
plants  included  in  the  highest  class  ordinarily  produce  leaves 
with  netted  veins  and  the  flowers  are  built  generally  upon  the 
plan  of  four  or  five  rather  than  upon  the  plan  of  three.  That 
is  to  say,  while  one  finds  three  sepals,  three  petals,  six  stamens, 
and  three  carpels  forming  the  fruit-rudiment  in  many  flowers 
of  lower-class  plants,  one  would  more  probably  find  four  or 
five  sepals,  four  or  five  petals,  four,  eight  or  some  other  number 


236  Minnesota  Plant  Life. 

of  stamens,  and  five  carpels,  or  more,  fused  together  to  make 
the  fruit-rudiment  in  the  flower  of  a  plant  belonging  to  the 
higher  class.  In  both  classes  of  higher  seed-plants  there  are 
many  variations  from  the  rule  and  in  some  plants  of  the  highest 
class,  flowers  very  similar  in  general  plan  to  those  of  the  lily 
might  be  observed.  Yet  the  differences  which  have  been 
pointed  out  are  fairly  general  and  in  most  instances  serve  to 
distinguish  the  proper  class  of  a  plant  in  question. 

The  highest  class,  comprising  over  120,000  species,  is  by  far 
the  richest  in  forms  of  any  in  the  vegetable  kingdom.  Two 
sub-classes  are  recognized,  in  each  of  which  are  grouped  a 
number  of  orders.  The  higher  sub-class  comprises  all  those 
forms  in  which  the  petals  are  normally  fused  together  by  their 
sides  to  make  a  corolla-tube — a  structure  of  which  the  honey- 
suckle, or  the  morning-glory  affords  typical  examples.  When, 
however,  the  petals  are  distinct  from  each  other  or  are  quite 
reduced  and  insignificant,  the  flower  is  regarded  as  typical  of 
the  lower  sub-class. 

Casuarina  trees.  The  first  and  lo\vest  order  of  the  highest 
class  includes  a  curious  family  of  trees,  the  casuarinas,  not  rep- 
resented in  North  America.  In  appearance  their  branches 
would  remind  one  of  those  of  the  horse-tail.  They  are  abun- 
dant in  northern  Australia  and  the  Malay  archipelago,  and  differ 
from  most  other  seed-producing  plants  in  forming  more  than 
one  large-spore  in  the  ovule,  so  that  in  a  single  seed  more  than 
one  female  plant  may  arise.  Another  odd  habit  of  the  casu- 
arinas— which  appears,  however,  in  some  of  the  other  families 
of  the  class — is  the  penetration  of  the  seed-rudiment  by  the 
pollen-tube,  not  through  a  canal  at  its  tip,  as  is  the  rule,  but 
through  a  cleft  in  the  base.  Therefore  the  seed-rudiment,  which, 
it  must  be  remembered,  is  equivalent  to  a  spore-case  in  the 
ferns,  may  be  regarded,  in  these  plants,  as  splitting  open  and 
partially  exposing  the  spores  inside — a  behavior  recalling  very 
strikingly  the  ordinary  opening  of  spore-cases  in  lower  forms. 

Lizard's-tails  and  peppers.  The  second  order  includes  four 
families  of  which  the  pepper  family  is  the  most  important. 
Here  belong  the  peppers  and  cubebs  from  which  spices  are 
obtained.  They  are  nearly  all  tropical  and  none  of  them  occur 
in  Minnesota. 


Minnesota  Plant  Life. 


237 


A  single  curious  little  plant,  the  lizard's-tail,  belonging  to  a 
related  family,  is  found  in  far  northern  Minnesota.  The  lizard's- 
tail  is  an  herb  with  heart-shaped  leaves  and  flowers  arranged 
in  little  spikes  like  those  of  the  dooryard  plantain.  There  are 
no  petals  or  sepals  and  the  stamens  grow  from  the  base  of  the 
ovary,  which  consists  of  three  or  four  carpels,  sometimes  fused 
and  sometimes  almost  separate.  From  four  to  eight  seeds  are 
formed  in  the  fruit  and  in  each  seed  there  is  an  abundant  albu- 
men. The  embryo  is  small  and  located  near  the  end  of  the 


FIG.  106.     Poplar  vegetation  of  burnt  district.    Near  Rat  Portage,  Ontario.     After  photograph 

by  the  author. 

seed,  imbedded  in  the  albumen.     These  plants  are  to  be  sought 
in  swamps  or  near  the  edges  of  small  woodland  lakes. 

Willows  and  poplars.  The  third  order  includes  but  a  single 
family — the  willow  family — to  which  the  willows  and  poplars 
belong.  About  eighteen  species  of  willow  and  seven  species 
of  poplar  grow  without  cultivation  in  Minnesota.  The  willows 
are  wind-pollinated  plants  with  rather  slender  leaves.  The 
poplars  are  insect-pollinated  and  have  generally  broad,  trian- 
gular or  heart-shaped  leaves.  This  family  of  plants  is  charac- 
terized by  separate  flowers,  the  staminate  and  pistillate  occur- 


Minnesota  Plant  Life. 


ring  in  different  clusters,  and  both  kinds  are  arranged  in  erect 
spikes  or  drooping  catkins.  The  fruit  is  an  oblong  or  rounded 
capsule  containing  small  seeds  with  numerous  white  silky  hairs 
instrumental  in  distribution  of  the  plantlets  in  currents  of  air. 
There  is  no  albumen  in  the  seeds. 

Poplars.  The  poplars  in  Minnesota  are  represented  by  the 
very  common  white  poplar,  the  large-toothed  poplar,  the  cot- 
tonwood,  the  balsam-poplar,  the  balm  of  Gilead,  the  silver- 
leafed  poplar — sometimes  called  silver-leafed  maple — and  the 
Lombardy  poplar.  The  last  two  are  not  native  plants,  but 
occur  spontaneously,  having  escaped  from  cultivation  in  some 

parts  of  the  state.  Of  them 
all,  the  white  poplar  is  the 
most  abundant  tree  through- 
out the  northern  part  of  the 
state,  and  is  not  uncommon 
in  the  southern  counties. 
This,  indeed,  is  the  most  widely 
distributed  tree  in  North 
America.  It  often  reaches 
a  height  of  seventy-five  or 
one  hundred  feet,  but  in  the 
region  of  the  Great  Lakes  does 
not  apparently  grow  so  large. 
The  wood  is  soft  and  is  of 
great  importance,  together 
FIG.  107.  cottonwood.  After  Britton  and  with  spruce,  as  the  variety  em- 

ployed  in  making  wood-pulp, 

from  which  paper  is  manufactured.  It  is  used  also  for  fire- 
wood, and  is  a  most  prominent  plant  in  burned  districts,  readily 
reaching  them  by  its  buoyant  air-distributed  seeds.  The  leaves 
are  hung  upon  stems  of  peculiar  shape  and  tremble  in  the  slight- 
est breeze. 

The  large-toothed  poplar  has  much  ampler  leaves  with  broad 
teeth  upon  their  margins.  By  these  characters  it  may  be  dis- 
tinguished from  the  white  poplar.  It  prefers  soil  damper  than 
does  its  relative  and  is  generally  found  upon  the  more  sheltered 
banks  of  lakes.  Its  wood  is  also  of  value  in  the  manufacture 
of  paper. 


Minnesota  Plant  Life. 


239 


The  balsam-poplar  has  longer,  sticky  leaves  and  the  balm 
of  Gilead — a  variety  with  more  spreading  branches — is  culti- 
vated as  a  shade  tree  in  some  parts  of  the  state.  The  leaves 
are  dark  green  on  one  side  and  dirty  brown  or  white  on  the 
other,  and  are  considerably  longer  than  those  of  any  other  Min- 
nesota species. 

The  cotton  wood,  which  may  be  distinguished  from  the  white 
poplar  by  the  glistening  paler  green  of  its  leaves,  is  an  abund- 
ant tree  throughout  the  state,  and  is  found  along  streams 
where  it  often  forms  considerable  forests.  Under  favorable 


FIG.  108.     Peach-leafed  willows  on  shore  of  stream.     After  photograph  by  Williams. 

conditions  it  may  grow  to  the  height  of  a  hundred  feet  with  a 
trunk  seven  or  eight  feet  in  diameter,  but  I  have  seen  none  in 
Minnesota  to  exceed  five  feet  in  thickness.  The  wood  is  of 
little  value  save  for  pulp  and  fuel.  In  the  older  towns  and  vil- 
lages of  Minnesota  the  cottonwood  has  been  freely  planted; 
but  it  is  not  regarded  as  the  most  desirable  of  shade  trees,  for 
it  is  always  dropping  something  from  its  boughs — either  stam- 
inate  flower-clusters,  cotton,  scales  or  leaves — and  it  litters  a 
lawn  or  street  throughout  the  spring  and  summer.  The  stam- 
inate  flowers  of  the  cottonwood  are  crimson  in  color,  borne  in 


240  Minnesota  Plant  Life. 

rather  dense  drooping  catkins.  The  pistillate  flowers,  produced 
on  other  trees,  are  green  in  color,  and  likewise  gathered  in 
pendent  clusters.  The  capsule  opens  by  three  clefts  and  is 
regarded  as  composed  of  three  carpels.  A  considerable  num- 
ber of  silky-tufted  seeds  are  produced  in  each  capsule. 

The  other  poplars  need  no  special  mention  since  they  are 
not  indigenous  to  the  state.  One  of  them,  the  Lombardy  pop- 
lar, with  its  spire-like  habit  of  growth,  is  an  attractive  and  val- 
uable ornamental  tree.  It  is  propagated  by  cuttings  and  seems 
to  have  lost  the  power  of  fruiting.  No  doubt  almost  all  the 

I: 


FIG.  109.  Clusters  of  willow  flowers;  on  the  left  the  pistillate  flowers  and  on  the  right  the 
staminate.  Each  pistillate  flower  consists  principally  of  a  single  fruit-rudiment,  and  each 
stamiiiate  flower  of  two,  or  sometimes  a  larger  number  of  stamens.  After  Atkinson. 

Lombardy  poplar  trees  in  America  might  be  traced  back  to  a 
single  poplar  egg.  The  tree  which  developed  from  the  em- 
bryo plantlet  was  originally  propagated  by  cutting  the  twigs 
and  planting  them  in  the  soil.  The  process  was  repeated  and 
in  this  way  a  vast  number  of  Lombardy  poplars  have  come  to 
•exist — a  very  odd  thing,  indeed,  when  one  thinks  of  it  and  com- 
pares it  with  the  behavior  of  animal  eggs. 

Willows.  The  willows  of  Minnesota  are  not  all  trees  like  the 
poplars.  The  majority  are  shrubs — some  of  them  low  bushes 
like  the  myrtle-leafed  willows  in  peat-bogs  and  tamarack 


Minnesota  Plant  Life. 


241 


swamps.  A  few,  however,  are  trees  and  of  goodly  size.  The 
distinctive  habitat  of  willows  is  along  the  banks  of  streams  and 
around  the  shores  of  lakes  or  marshes.  Their  twigs  are  used 
in  the  manufacture  of  wickerware ;  and  bushed-willows  or  pol- 
larded willows,  are  favorite  plants  for  hedge-rows  in  the  east 
and  in  England,  but  are  not  so  frequent  in  Minnesota.  The 
two  most  conspicuous  willow  trees  of  the  state  are  the  black 
willows  with  their  slender  leaves  bearing  conspicuous  stipules 
at  the  base,  abundant  in  the  north,  and  the  peach-leafed  wil- 


r 


FIG.  110.     Beach  vegetation,    Garden   Island,   lyake  of  the   Woods.     The  long-leafed  willow 
forms  the  outer  zone,  and  the  black  willow  the  inner.     After  photograph  by  the  author. 

lows,  with  much  broader  leaves  and  devoid  of  stipules  on  ma- 
ture twigs,  more  common  in  the  south. 

The  hoary  willow,  the  gray  willow,  the  pussy-willow,  the 
heart-leafed  willow,  the  myrtle-leafed  willow  and  the  long- 
leafed  or  sand-bar  willow  are  encountered  ordinarily  as  low 
shrubs  up  to  ten  or  twelve  feet  in  height.  The  familiar  "pussies" 
of  early  spring  are  the  spicate  flower-clusters  of  some  willow 
from  which  the  bud-scales  have  opened  or  fallen,  revealing  the 
branch  covered  with  bractlets  in  the  axils  of  which  the  flowers 
will  open.  The  edges  of  the  bractlets  have  silky  hairs  which 

'7 


242  Minnesota  Plant  Life. 

serve  to  protect  the  flower-buds  during  the  cold  nights  or  oc- 
casional freezing  weather  of  early  spring. 

As  beach  plants,  the  long-leafed  willow,  the  hoary  willow, 
the  heart-leafed  willow,  the  shining-leafed  willow  and  a  few 
others  are  common,  especially  along  sand-bars,  where  there  is 
considerable  spray  from  the  surf.  At  Lake  of  the  Woods  some 
very  interesting  willow-clothed  beaches  have  been  observed. 
Different  species  of  willows  on  such  beaches  often  arrange  them- 
selves in  zones,  one  variety  nearer  the  water,  and  another  far- 
ther back.  Some  of  the  willows,  notably  the  hoary  willow  and 
the  heart-leafed  willow,  along  the  shores  of  northern  lakes, 
grow7  in  a  very  regular  more  or  less  hemispherical  fashion,  re- 
sembling the  trimmed  shrubs  of  some  city  park. 

The  bark  of  the  willow  is  bitter  and  is  sometimes  used  as  a 
febrifuge  in  place  of  quinine,  but  it  is  not  particularly  efficacious. 


Chapter  XXVII. 

From  Bayberries  to  Oaks,  Elms  and  Nettles. 

if 

Bayberries.  The  fourth  order  includes  but  a  single  family, 
of  which  two  species  grow  in  Minnesota — the  bayberry,  found 
on  lake  shores  along  the  international  boundary,  and  the  sweet- 
fern,  rather  abundant  in  the  northern  part  of  the  state  and  ex- 
tending south  to  the  vicinity  of  Minneapolis.  These  plants 
are  shrubs,  their  leaves  dotted  with  resin  glands,  and  the  name 
"sweet-fern"  is  given  on  account  of  the  scent  which  arises  from 
the  glands.  The  two  sorts  of  flowers  are  separate  and  in  cat- 
kins somewhat  like  those  of  the  willows  but  shorter  and  plumper 
in  appearance.  The  fruit  is  a  nut  or  stone  fruit,  differing  in 
this  respect  from  the  willow  fruits,  which  are  capsules.  The 
leaf  of  the  sweet-fern  is  especially  characteristic,  resembling  in 
shape  a  willow  leaf  with  deep  narrow  incisions  along  the  margin. 

The  fifth  and  sixth  orders  are  not  represented  in  Minnesota. 
One  of  them  contains  a  few  species  of  New  Caledonian  plants, 
the  other,  one  species  found  in  the  southern  United  States. 

Walnuts  and  hickories.  The  seventh  order  comprises  but  a 
single  family,  in  which  are  classified  the  walnuts  and  hickories, 
both  represented  in  Minnesota.  There  are  present  two  species 
of  walnuts — the  black  walnut  and  the  butternut — and  three 
species  of  hickories — the  white  hickory  or  shell-bark,  the  pig- 
nut hickory,  and  the  swamp  hickory.  The  walnut  family  is  a 
group  of  trees  with  compound  leaves  and  separated  flowers. 
The  staminate  flowers  stand  in  catkins  and  are  furnished  with 
a  perianth.  The  pistillate  flowers  are  solitary  or  in  small 
groups.  The  ovary  is  one-chambered  and  contains  a  single 
seed-rudiment.  The  fruit  is  similar  to  that  of  a  peach  in  which 
the  fleshy  part  should  split  and  separate  as  three  or  more  husks. 
The  seed  is  large,  inclosed  in  the  stony  inner  layers  of  the  fruit, 
the  whole  constituting  the  well-known  walnut,  hickory-nut  or 


244 


Minnesota  Plant  Life. 


pecan.  There  is  no  albumen  in  the  seed  and  the  two  seed- 
leaves  are  large,  wrinkled  and  oily,  forming  the  "meat"  of  the 
nut.  The  black  walnut  occurs  in  the  southern  part  of  Minne- 
sota, where  it  is  found  in  low  glades  along  streams.  Almost 
all  the  large  trees  have  been  cut  for  their  very  valuable  wood, 
useful  in  cabinet  making.  This  is  of  a  rich,  dark  brown  color 
and  takes  a  high  polish.  The  butternut  is  more  abundant  and 
is  a  frequent  inhabitant  of  groves  in  the  river  valleys,  especially 

through  the  southern  part  of 
the  state.  It  is  not  commonly 
more  than  forty  or  fifty  feet 
high  in  Minnesota,  though  it 
is  known  to  grow  twice  as  tall. 
The  wood  is  of  a  light  brown 
color,  easily  polished  and  of 
much  value  in  the  manufacture 
of  furniture  and  cabinet  work, 
though  by  no  means  the  equal 
of  the  black  walnut. 

Hickories.  The  three  kinds 
of  hickories  in  the  state  may 
be  recognized  by  their  leaflets, 
nuts  and  buds.  In  the  shell- 
bark  hickory  the  leaflets  are 
from  five  to  seven  in  number, 
with  hairy  margins.  The  nut 
is  four-angled,  pale  or  whitish 
in  color.  In  the  pig-nut  hick- 
ory, with  the  same  number  of 

leaflets,     these      are      USUally 
,  , .     ,  - 

smooth  or  slightly  furry,  but 
not  hairy  at  the  margin.  The  nut  is  oblong,  with  a  slightly 
bitter  kernel.  In  the  swamp  hickory  the  leaflets  are  from  five 
to  nine  in  number,  the  nut  thin-shelled  and  short.  The  buds 
in  winter  are  yellow.  The  wood  in  all  these  plants  is  very 
heavy,  strong  and  tough,  and  is  used  in  the  manufacture  of 
wagon-tongues  and  plow-handles,  while  the  young  saplings  of 
the  swamp  hickory  are  split  and  bent  into  barrel-hoops.  The 
nuts  are  common  in  markets,  but  are  not  so  agreeable  to  the 


FIG.  111.     Hickory  trees.    l,ake  Minnetonka. 
After  photograph  by  Williams. 


Minnesota  Plant  Life. 


245 


taste  as  the  pecan  nuts,  which  are  derived  from  a  species  of 
hickory  that  does  not  grow  in  Minnesota.  Hickories  are  often 
a  hundred  feet  in  height,  with  tall  trunks  two  feet  in  diameter 


FIG.  112.     Ironwoo 


d  oaks.     The  smaller  trees  are  ironwoods  and  hop-hornbeams.     l,ake 
Calhoun.     After  photograph  by  Hihhard. 


at  the  base.     They  are  among  the  most  valuable  of  the  hard- 
wood timber  trees  of  the  state. 

The  eighth  order  comprises  two  families,  one  including  the 
hazels,  ironwoods,  hop-hornbeams,  birches  and  alders;  the  other 


246  Minnesota  Plant  Life. 

the  beeches  and  chestnuts,  not  represented  in  Minnesota,  and 
the  oaks  which  form  a  large  and  characteristic  portion  of  the 
hardwood  forest  of  the  state. 

Ironwoods.  Of  ironwoods  there  is  a  single  species  in  Min- 
nesota, known  also  as  the  water-beech  or  hornbeam.  This 
plant  is  a  small  tree  with  very  strong,  tough  wood.  It  is 
found  principally  along  streams.  It  has  the  leaves  of  a  birch, 
but  when  in  fruit  displays  each  of  its  little  nuts  at  the  base  of 
a  large  three-lobed  bract  shaped  somewhat  like  a  spear-head. 
By  means  of  these  bracts  and  also  by  the  rough  bark,  quite 
unlike  birch-bark,  the  ironwoods  may  be  distinguished.  Re- 
lated to  them  are  the  hop-hornbeams,  the  fruit  clusters  of  which 
look  very  much  like  hops,  while  the  general  appearance  of  the 
tree  is  similar  to  that  of  the  ironwood.  An  examination  of 
such  an  hop-like  fruit  cluster  will  show  that  it  is  an  axis  upon 
which  little  nuts  are  formed,  each  one  inclosed  in  a  membranous 
sac  structurally  equivalent  to  the  spear-shaped  bract  of  the  iron- 
wood. 

The  hazels.  The  hazels,  of  which  there  are  two  varieties  in 
the  state,  are  shrubs  with  broad  notched  leaves.  They  pro- 
duce their  staminate  flowers  in  catkins  and  the  pistillate  flowers 
in  very  inconspicuous  little  buds  from  which  the  stigmas  of  the 
pistils  protrude  as  red  threads.  In  the  common  hazelnut,  which 
is  so  abundant  as  underbrush  in  the  woods,  the  nuts,  when 
mature,  are  inclosed  in  ragged  scales  not  prolonged  very  much 
beyond  the  ends  of  the  nuts.  In  the  beaked  hazelnut,  a  some- 
what larger  bush,  ten  or  fifteen  feet  in  height,  the  nuts  are  in- 
closed in  scales  which  grow  out  into  a  long  tubular  beak,  a 
structure  by  which  this  plant  is  easily  distinguished  from  the 
more  common  variety.  The  nuts  of  the  hazels  are  much  larger 
than  those  of  the  ironwoods  and  hornbeams,  are  edible  and  are 
gathered  in  quantities  in  the  autumn. 

Birches.  Of  birches  there  are  six  species  in  Minnesota,  the 
black  birch,  the  canoe  or  paper  birch,  the  river  or  red  birch, 
the  yellow  or  gray  birch,  the  low  birch  or  tag-alder,  and  the 
scrub  or  glandular  birch.  These  plants  range  in  size,  in  the 
different  species,  from  large  trees  to  low  bushes,  but  may  be 
recognized  in  most  instances  by  their  bark,  which  peels  off  in 
thin  layers,  most  easily  in  the  canoe  birch,  but  with  very  little 


Minnesota  Plant  Life. 


247 


difficulty  in  the  others.  Of  the  trees,  the  canoe  birch  will  be 
known  by  its  white  bark,  the  river  birch  by  the  stems  of  the 
fruiting  catkins  and  the  brown  or  greenish-brown  bark,  the 
black  birch  by  the  sessile  fruiting  catkins  and  the  leaves  of  shin- 
ing green,  the  yellow  birch  by  the  dull  green  color  of  the  leaf, 
otherwise  like  the  black  birch.  All  of  these  just  mentioned  are 
trees,  while  the  rest  are  shrubs.  In  the  low  birch  the  twigs 
are  not  covered  with  glandular  pimples,  but  such  are  present 
on  the  twigs  of  the  glandular  birch.  Of  all  the  birches  the 


FIG.  113.     The  paper  or  canoe  birch.     After  photograph  by  Williams. 

canoe  birch  is  the  most  interesting,  on  account  of  the  peculiar 
bark  that  plays  so  important  a  part  in  the  domestic  arts  of  the 
Indians  who  employ  it  in  the  manufacture  of  a  great  variety 
of  useful  objects.  Their  canoes  and  the  houses,  dishes,  bas- 
kets, drinking-cups  and  scrolls  for  writing  are  produced  from 
birch-bark;  while  from  the  wood  they  manufacture  a  variety 
of  tools,  snow-shoe  frames,  sledge-runners  and  tepee-poles.  By 
the  whites,  birch  wood  is  employed  in  cabinet  making,  for 
spools,  for  shoe-pegs  and  for  lasts.  The  wood  of  the  red  birch 
or  river  birch  is  of  particular  value  in  the  manufacture  «>f  fur- 


248 


Minnesota  Plant  Life. 


Minnesota  Plant  Life. 


Minnesota  Plant  Life. 


249 


niture,  being  utilized  as  an  imitation  of  mahogany.  For  this 
purpose,  too,  the  wood  of  the  black  birch  is  even  more  excel- 
lent. This  species,  however,  occurs  but  sparingly  in  Minne- 
sota and  is  found  only  in  the  extreme  northern  part  of  the  state. 
It  is  from  this  species  that  birch-oil  and  the  extract  used  in 
flavoring  birch  beer  are  manufactured.  Of  the  shrubby  birches 
the  most  abundant  is  the  low  birch  which  is  found  in  peat-bogs 
pretty  commonly  through- 
out the  state. 

Alders.  Related  to  the 
birches  are  the  alders,  of 
which  two  varieties  occur  in 
Minnesota,  the  green  alder 
and  the  black  alder.  These 
may  be  distinguished  from 
the  low  birch,  which  they 
resemble,  by  their  more  en- 
tire leaves  and  short,  com- 
pact, cone-like  clusters  of 
nutlets.  The  low  birch  has 
rather  more  elongated 
spikes  of  pistillate  flowers, 
two  and  a  half  times  as  long 
as  they  are  thick,  while  the 
alder  spikes  are  about  half  - 
as  long  again  as  thick.  The 
alders  are  to  be  looked  for 

in     tamarack     SWampS    Or    in  FIG.  115.     An  oak  twig  with  leaves  and  both  sort-* 

j              i  of  flowers.     The  one  with  three  prongs  is  the 

Open     WOOdS,     Where,     eSpe-  pistillate  flower;  the  other,  with  five  stamens, 

daily    in    damp    places,    they  is  the  rtaminate.     The  *aminate  flowers  grow 

3  in  drooping  clusters.     After  Atkinson. 

may  form  an  underbrush. 

Oaks.     There  are  in  Minnesota  sev^n  species  of  oaks,  the 
red,  the  scarlet,  the  black,  the  white,  the  bur,  the  chestnut  and 
the  scrub  chestnut-oak.     Oaks  form  a  large  genus  of  plants, 
comprising  some  three  hundred  species  and  well  distributed 
throughout  the  temperate  regions  of  the  northern  hemisphere 
and  at  high  altitudes  in  the  tropics.     There  are  some 
species  in  North  America.     They  are  distinguished  by  the  fru: 
known  as  the  acorn,  consisting  of  a  nut  or  one-seeded  fruit. 


25° 


Minnesota  Plant  Life. 


inclosed  within,  or  standing  in  a  cup  composed  of  numerous 
bractlets  ordinarily  grown  together  and  woody.  In  some  oaks 
the  fruit  matures  within  a  year,  but  in  other  varieties  a  longer 
time  is  required.  Oaks  are  employed  for  a  variety  of  purposes 
— as  firewood,  in  the  manufacture  of  timbers  in  which  great 
durability  is  demanded,  and  as  plants  from  which  tan-bark  may 
be  procured.  The  acorns  are  eaten  by  domestic  animals,  and 
the  various  species  are  prized  as  shade-trees. 


FIG.  116.     Oaks  and  blue   flags.     A  marshy  place   in   the   oak-woods.     After  photograph  by 

Williams. 

The  different  varieties  in  Minnesota  may  be  thus  distin- 
guished :  Of  those  forms  in  which  it  takes  the  acorn  two  years 
to  mature,  the  red  oak  has  leaves  green  on  both  sides  and  the 
acorn  cup  much  broader  than  high,  while  in  the  scarlet  oak  the 
cup  of  the  acorn  is  about  as  high  as  broad,  the  leaves  are  smooth 
on  each  side,  and  the  inner  bark  gray.  In  the  black  oak,  which 
is  much  like  the  scarlet  oak  in  appearance,  the  leaves  on  the 
under  side  develop  a  few  hairs  where  the  veins  branch,  and  the 
inner  bark  is  orange  in  color.  In  all  three  species  which  have 
been  mentioned  the  acorns  do  not  mature  until  the  autumn  of 


Minnesota  Plant  Life. 


251 


the  second  season.  In  the  scarlet  oak  the  foliage  turns  scarlet 
red  in  autumn,  while  in  the  black  oak  the  leaves  turn  brown. 
In  this  way  the  three  related  species  may  be  distinguished.  In 
some  instances,  it  should  be  mentioned,  the  inner  bark  of  the 
scarlet  oak  is  red  rather  than  gray.  The  other  Minnesota  oaks 
mature  their  acorns  in  the  autumn  of  the  first  year.  Of  these 
the  white  oak  is  distinguished  by  its  deeply  lobed  leaves  and 
shallow  cups,  while  the  bur-oak  has  the  cup  deep  and  com- 
posed of  scales  which  form  a  bur-like  growth  different  from  the 
smooth  hard  cup  of  the  white  oak.  In  the  remaining  native 
oaks  the  leaves  are  notched 
but  are  not  lobed  in  the  char- 
acteristic oak  fashion,  and  in 
both  of  them  the  acorns  are 
sessile  on  the  branches.  The 
chestnut-oak  is  a  tall  tree  with 
grey  bark  and  has  a  chestnut- 
like  aspect.  The  scrub  chest- 
nut-oak is  a  shrub  with  the 
leaves  considerably  broader 
than  in  the  chestnut-oak 
proper. 

Some  of  the  oaks,  notably 
the  black  oak,  cling  to  their 
leaves  for  a  long  time  after  the 
frosts  have  killed  them,  some- 
times even  throughout  the 
winter.  This  habit  is  possibly 

the  indication  of  an  original  southern  range  for  the  black  oak 
and  a  late  extension  of  its  range  to  the  north,  so  that  it  has  not 
fully  learned  how  to  cut  its  leaves  from  the  twigs  as  the  other 
more  northern  varieties  are  able  to  do.  The  bur-oaks  in  Min- 
nesota, together  with  the  black  oaks,  form  oak-barrens.  These 
wastes,  covered  with  grotesquely  branching  trunks,  form  pic- 
turesque forests  in  the  central  part  of  the  state. 

The  ninth  order  includes  three  families,  the  elms  with  the 
hackberries,  mulberries  and  Osage  oranges;  the  India-rubber 
trees,  figs,  hemps  and  hops,  and  the  various  kinds  of  nettles. 


FIG.  117.     American  elm.     After  Britton  and 
Brown. 


252 


Minnesota  Plant  Life. 


Elms.  Of  the  elms  there  are  represented  in  Minnesota  three 
varieties,  and  one  species  of  hackberry.  The  elms  which  are 
present  in  the  state  are  the  white  or  American  elm,  the  slippery 
or  red  elm,  and  the  rock-  or  cork-elm.  Their  flowers  are  small, 
clustered  or  solitary,  quite  devoid  of  petals.  The  ovary  is  one 
or  two-celled,  with  a  solitary  seed.  The  fruit  of  the  elm  is 
winged.  In  the  hackberry  it  is  a  berry-like  nut.  The  seeds 
have  little  albumen.  The  three  varieties  of  elm  which  occur 
in  Minnesota  may  be  distinguished  by  the  following  characters : 
When  the  young  fruit  is  very  hairy  and  the  branches  are  without 


FIG.  118.    American  elm.     L,ake  Miunetonka.     After  photograph  by  Williams. 

corky  wings,  the  tree  is  the  white  elm.  When  the  fruit  has  no 
hairs,  is  larger  and  the  twigs  are  not  supplied  with  corky  wings 
the  tree  is  the  slippery  or  red  elm.  When  the  fruit  is  hairy 
and  the  branches  are  provided  with  curious  flat  cork  wings, 
especially  prominent  on  the  young  twig,  the  tree  is  the  rock- 
or  cork-elm.  All  of  these  occur  in  similar  regions  and,  together 
with  the  basswoods,  maples  and  oaks,  form  the  most  abundant 
growths  in  the  hardwood  forests  of  the  central  part  of  the  state. 
Elms  are  generally  to  be  recognized  by  the  uneven  bases  of 
their  leaves,  by  the  strong  development  of  the  terminal  buds 


Minnesota  Plant  Life.  253 

of  their  branches,  and  by  the  little,  oval,  flattened  fruits  with 
wings  on  each  side  or  extending  entirely  around  the  middle. 
The  wood  of  the  elm  is  tough  and  is  employed  for  ox-yokes, 
the  handles  of  tools  and  portions  of  farm  machinery.  The  inner 
bark  of  the  slippery  elm  is  mucilaginous  and  is  thought  to  have 
some  medicinal  virtue.  It  is  frequently  gathered  by  children. 

Hackberries.  The  hackberry,  which  in  its  flowers  and  foli- 
age much  resembles  the  elms,  is  distinguished  by  the  produc- 
tion of  a  berry-like  nut.  It  is  abundant  throughout  the  south- 
ern part  of  the  state  and  occurs  in  a  few  localities  far  to  the 
north ;  as  for  example,  on  Sable  island,  Lake  of  the  Woods. 
The  trees  are  valuable  shade  trees  and  are  common  along  the 
streets  of  towns  and  villages. 

Mulberries  and  hops.  The  mulberries  are  represented  in 
Minnesota  by  the  red  mulberry — a  species  reported  from  the 
southern  part  of  the  state.  It  is  a  tree  with  fruits  superficially 
resembling  those  of  the  red  raspberry.  These  are  not,  however, 
like  those  of  the  raspberry,  produced  from  a  single  flower,  but 
are  rather  aggregates  of  fruits  like  the  spikes  of  the  birch,  or 
the  catkins  of  the  poplar.  The  foliage  of  a  mulberry  is  not 
unlike  that  of  the  elm.  The  fruit-clusters  are  edible  and  the 
tree  is  both  ornamental  and  valuable  in  cultivation.  The  com- 
mon hop,  related  to  the  mulberries,  is  a  twining  vine  with  rough 
stem  and  foliage,  and  found  in  thickets  and  woodsides  through- 
out the  state.  It  is  more  abundant  in  the  central  and  northern 
portions  of  the  state  than  southward.  The  general  appearance 
of  the  fruiting  area  is  like  that  of  the  hop-hornbeam,  but  the 
floral  structure  is  in  most  of  the  essential  details  like  that  of  the 
mulberries.  Hops  are  of  value  in  the  manufacture  of  yeasts  and 
have  besides  a  distinct  medicinal  value.  They  are  gathered  as 
herbs  in  Minnesota  but  not,  so  far  as  has  been  learned,  on  a 
commercial  scale. 

Hemp.  The  hemp,  introduced  from  Asia,  is  a  very  abund- 
ant roadside  weed  and  a  denizen  of  waste  fields  throughout  the 
state.  It  is  a  robust  annual  herb,  growing  to  a  height  of  more 
than  ten  feet,  forming  thickets,  and  really  becoming  a  sort  of 
herbaceous  tree.  The  inner  fibrous  bark  is  exceedingly  tough 
and  is  pounded  out  of  the  stem  by  special  machinery  and  con- 
verted into  rope  and  mattings.  It  is  not  generally  employed 


254  Minnesota  Plant  Life. 

in  Minnesota  for  these  purposes,  though  it  is  evidently  capable 
of  producing  as  strong  a  fibre  here  as  elsewhere.  The  hemp 
leaves  are  divided  into  from  four  to  eight  or  nine  slender  lobes 
arranged  in  palmate  fashion.  The  staminate  flowers  are  ar- 
ranged in  panicles,  while  the  pistillate  stand  in  short  leafy  spikes. 
Nettles.  The  nettles  are  represented  in  Minnesota  by  the 
stinging  and  the  slender  nettles,  the  wood-nettles,  the  clear- 
weeds,  the  false  nettles  and  the  pellitories.  The  first  two  va- 
rieties of  nettles,  one  of  which  is  introduced,  are  distinguished 
by  the  different  shape  of  their  leaves.  In  the  stinging  nettle 


FIG.  119.     Roadside  vegetation  of  nettles  and  vines.     Winter  aspect.     After  photograph  by 

Williams. 

the  leaves  are  ovate  in  outline,  while  in  the  slender  nettle  they 
are  lance-shaped  and  slender  pointed.  Both  of  these  plants  are 
provided  with  peculiar  stinging  hairs,  consisting  of  cells  with 
very  sharp  points  and  swollen  bases  around  which  a  group  of 
cells  comes  up  like  a  cup.  Hairs  of  this  sort  are  found  on  both 
the  leaves  and  stem.  Upon  being  brushed  against,  the  ends 
of  these  hairs  break,  forming  a  chisel-like  point  which  penetrates 
the  flesh  and  the  cup  of  cells  around  the  base  of  the  hair  con- 
tracts and  injects  irritating  poison,  very  much  as  if  from  a  syr- 
inge. The  peculiar  stinging  sensation  which  arises  when  one 
touches  a  nettle  is  a  result  of  this  injection  of  acid  into  the  flesh. 


Minnesota  Plant  Life. 


255 


The  wood-nettles,  from  their  name  to  be  looked  for  in  the 
forest,  have  tall  stems  as  much  as  four  feet  in  height,  stinging 
hairs  like  the  ordinary  nettles,  and  flowers  disposed  in  axillary 
compound  clusters.  The  leaves  are  thin,  shaped  much  like 
those  of  the  stinging  nettle,  and  provided  with  a  solitary  stip- 
ule which  often  falls  off.  The  clearweecls  have  no  stings.  The 
leaves  are  opposite  and  the  stems  are  translucent  and  succulent, 
resembling  the  stems  of  the  touch-me-not.  The  leaves  are  del- 
icate and  thin.  The  flower  clusters  are  borne  on  short  stems 
in  the  axils  of  the  leaves.  The  clearweed  is  a  shade-plant, 
preferring  deep  woods  where  there  is  an  abundance  of  moisture. 
The  false  nettles  resemble  the  true  nettles  in  outward  appear- 
ance and  are  found  in  similar  localities.  They  have,  however, 
no  stinging  hairs.  The  pellitories  have  willow-shaped  leaves, 
are  devoid  of  stipules  and  develop  the  flowers  in  little  clusters 
at  the  bases  of  alternate  leaves.  The  flower  clusters  are  of  the 
general  nettle  type. 

The  tenth  order  is  best  developed  in  Australia  and  South 
Africa  and  has  no  native  forms  in  Minnesota. 


Chapter  XXVIII. 

From  Sandalwoods  to  Buttercups* 

Toad-flaxes.  The  eleventh  order  includes  six  families,  one 
of  which,  the  sandalwood  family,  is  represented  in  Minnesota 
by  three  species  of  toad-flax.  In  this  same  order  are  included 
the  mistletoes  and  other  curious  parasitic  forms  of  vegetation. 
The  toad-flaxes  belong  to  a  group  known  as  root  parasites. 
They  seem  to  be  independent  plants,  but  if  their  roots  are  care- 
fully dug  up  it  will  be  found  that  they  have  attached  themselves 
to  the  roots  of  other  plants  growing  near  them,  and  that  from 
these  other  plants  they  are  sucking  their  food.  They  are,  in 
Minnesota  forms,  slender  herbs  with  leaves  shaped  like  those  of 
a  willow  and  with  flowers  in  corymb  clusters,  or  cymes.  The 
fruits  are  drupes  or  nuts.  There  is  abundant  albumen  in  the 
seed,  but  the  embryo  is  small  and  imbedded  near  one  end.  The 
berries  of  one  of  the  toad-flaxes  are  of  red  color  and  are  edible. 
These  plants  occur  in  dry  or  moist  soil,  and  one  variety  is  very 
common  throughout  the  state.  They  ordinarily  have  a  rather 
peculiar  brownish-green  foliage — except  the  pale  toad-flax,  of 
which  the  leaves  are  lighter  green.  Some  exotic  sandalwoods 
occur  as  trees,  and  from  them  the  highly  scented  sandalwood 
of  jewel-boxes  is  obtained. 

Wild  gingers.  The  twelfth  order  comprises  three  families, 
two  of  which  are  remarkable  aggregations  of  alien  parasitic  forms, 
while  the  other  includes  the  wild  ginger  and  pipe-vine  or  Dutch- 
man's-pipe  of  Minnesota.  The  parasitic  Rafflesias,  which  be- 
long to  this  order,  are  among  the  most  extraordinary  of  plants. 
One,  which  is  found  in  the  island  of  Sumatra,  is  famous  for 
having  the  largest  flower  in  the  world,  over  a  yard  in  diameter, 
of  the  color  of  livid  flesh,  and  of  a  very  penetrating,  unpleasant 
odor.  These  flowers  originate  as  buds,  resembling  cabbage 
heads,  upon  the  exposed  roots  of  certain  Sumatran  trees  or 
vines.  The  vine  or  root  has,  however,  no  structural  connec- 
tion with  the  cabbage-head  bud.  This  is  developed  upon  a 
curious  parasitic  plant-body  that  lives  within  the  tissues  of  the 


Minnesota  Plant  Life.  257 

vine,  bursting  its  way  out  when  about  to  flower.  The  flower 
is  much  more  conspicuous  than  the  rest  of  the  Rafflesia  plant- 
body.  Some  small  relatives  of  the  Rafflcsias  are  found  on  certain 
pod-bearing  trees  in  the  southern  states.  Their  little  flowers 
burst  through  the  bark  of  the  twig  in  which  the  plant-bodies 
are  growing,  thus  apparently  producing  the  remarkable  phe- 
nomenon of  twigs  with  flowers  growing  in  the  crevices  of  the 
bark.  Here,  however,  as  in  the  Sumatran  variety,  the  twig  is 
only  the  host-plant  and  the  flower  is  a  portion  of  the  internal 
parasite. 

The  two  Minnesota  members  of  the  order  are  not  parasites, 
but  are  independent  green  plants.  The  wild  ginger,  of  which 
several  species  are  known  to  exist  in  the  United  States,  is  met 
with  in  Minnesota  on  shaded  banks  of  ravines  where  the  root- 
stocks  of  the  plant,  branching  and  scented,  send  up  short  erect 
stems  usually  with  a  pair  of  large  kidney-shaped  leaves  and  pro- 
ducing single,  purplish-brown  flowers  very  close  to  the  ground. 
The  calyx  of  the  flower  has  three  leaves  with  slender  pointed 
tips.  These  are  recurved  in  the  Minnesota  variety.  The  calyx 
is  fused  with  the  surface  of  the  six-chambered  fruit-rudiment 
which  develops  numerous  seeds  in  two  rows  in  each  chamber. 
When  ripe,  the  fruit  is  a  capsule  inclosed  in  the  calyx,  and  it 
bursts  irregularly. 

Pipe-vines.  The  pipe-vines  are  twining  vines  with  alternate 
leaves — in  the  Minnesota  species  heart-shaped.  Curious  irreg- 
ular tubular  flowers  are  formed,  destitute  of  petals  and  with  the 
calyx  adhering  to  the  base  of  the  ovary.  The  edge  of  the  tubu- 
lar calyx  is  divided  into  three  lobes  and  the  flower  is  curved 
into  a  horse-shoe  shape.  These  remarkably  shaped  flowers  are 
insect-traps.  Insects  are  induced  to  enter  them  and  are  forcibly 
detained  as  prisoners  until  they  can  be  covered  with  pollen. 
They  are  then  released  to  visit  some  other  plant.  The  pipe-vine 
is  found  only  in  the  southeastern  counties  of  Minnesota,  -while 
the  wild  ginger  is  abundant  throughout  the  state. 

The  thirteenth  order  includes  a  single  family  in  which  are 
gathered  the  true  sorrels  and  docks,  the  rhubarbs,  the  buck- 
wheats and  the  smartweeds. 

Docks  and  smartweeds.  In  Minnesota  there  are  ten  vari- 
eties of  docks  and  about  twenty  five  of  knotweeds  or  smart- 

18 


258  Minnesota  Plant  Life. 

weeds.  The  smallest  of  the  docks  has  spear-head  shaped  leaves 
and  is  known  as  sorrel.  The  other  docks  are  some  of  them 
large-leaved  plants  most  luxuriant  in  marshes  or  swamps. 
Among  them  are  the  water-,  the  swamp-,  the  yellow,  the  golden, 
the  red-veined,  the  pale,  and  the  curly-leaved  docks,  differing 
principally  in  leaf  characters.  The  only  one  in  Minnesota  with 
sour  leaves  is  the  sorrel,  and  on  account  of  this  pleasant  acid 
taste  the  leaves  are  often  picked  and  eaten.  These  sorrels  are 
not  to  be  confused  with  the  sheep-sorrel,  in  wrhich  the  leaves  are 
shaped  like  clover  leaves, — an  entirely  different  kind  of  plant. 
The  different  species  of  dock,  besides  by  their  leaf  characters, 
are  to  be  distinguished  by  the  wings  on  the  fruits. 

The  smartweeds,  knotweeds,  or  bindweeds  fall  into  three 
groups  of  species;  some,  in  which  the  leaves  are  shaped  like 
those  of  the  willow,  others,  in  which  the  leaves  are  small  and 
slender,  and  still  others  with  heart-shaped  or  arrow-shaped 
leaves  and  twining  or  climbing  stems.  The  forms  with  willow- 
shaped  leaves  are  known  under  the  general  name  of  smartweeds ; 
those  with  the  small  leaves  are  called  knotweeds,  jointweeds, 
knot-grass  or  doorweeds,  while  those  with  arrow-shaped  or 
heart-shaped  leaves  are  termed  bindweeds,  false  buckwheat  or 
tear-thumbs.  They  are  all  similar  in  the  structure  of  their  flow- 
ers and  fruits.  One  variety,  the  water-smartweed,  produces  its 
stem  under  the  water  and  sends  its  leaves  to  the  surface,  where 
they  float  like  the  leaves  of  the  pond-lily.  The  flowers  are 
clustered  in  bright  pink  spikes  thrust  above  the  surface  of  the 
water.  Another  kind  with  similar  habit  is  found  as  a  surf-plant 
in  northern  lakes.  The  ordinary  smartweeds  grow  in  moist 
soil  and  ditches,  where  their  bright  pink  or  red  spikes  of  flowers 
are  conspicuous  objects.  The  knotweeds  are  common  mat- 
plants  of  dooryards.  In  most  of  the  varieties  stipules  at  the 
bases  of  the  leaves  coalesce  and  form  tubular  sheaths  around 
the  stem.  The  bindweeds  or  false  buckwheats  occur  either  as 
twining  vines  with  heart-shaped  leaves  and  flowers  like  those 
of  the  buckwheat,  or  they  grow  with  slender  erect  stems  reclin- 
ing against  the  vegetation  near  them  and  supporting  them- 
selves by  sharp  recurved  prickles.  These. are  known  as  tear- 
thumbs,  and  belong  to  a  small  adaptational  group  of  hook- 
climbing  plants. 


Minnesota  Plant  Life. 


259 


The  fourteenth  order  includes  the  goosefoots  or  pigweeds, 
and  the  amaranths,  known  also  as  pigweeds,  redroots  or  tumble- 
weeds,  including  the  coxcombs  and  one  variety  of  water  hemp. 
Here  also  are  the  fotir-o'clocks,  pokeweeds,  ice-plants,  carpet- 
weeds,  purslanes  and  portulacas,  pinks,  cockles  and  catchflies, 
besides  some  other  families  not  represented  in  Minnesota. 

Pigweeds.  The  goosefoots  are  represented  in  Minnesota  by 
about  fifteen  species,  many  of  which  are  introduced.  Here  are 
the  common,  scurfy-leaved,  pale  pigweeds  of  farm-yards  and 
roadsides.  Several  sorts  of  these  pigweeds  occur  in  the  state. 
Here  are  also  to  be  placed  the 
winged  pigweeds,  plants 
found  on  lake  shores,  espe- 
cially upon  sandy  beaches  in 
the  central  part  of  the  state, 
and  the  bugseeds,  abundant 
on  the  beaches  of  Mille  Lac 
and  near  Duluth  —  also  the 
blites  on  the  shore  of  Lake 
Superior,  and  two  salt-marsh 
plants  very  rare  in  Minnesota, 
but  reported  from  salt  marshes 
in  the  Red  river  valley. 

Glassworts.  One  of  these 
salt-marsh  plants,  the  glass- 
wort,  is  a  curious,  leafless,  suc- 
culent organism,  resembling 
some  slender  cactus-forms.  In  color  it  is  green  during  the 
summer,  but  turns  red  in  autumn.  The  stem  is  from  six  inches 
to  two  feet  tall,  repeatedly  branched  and  provided  with  tiny 
scales  at  the  nodes  of  the  fleshy  branches.  These  scales  are  all 
that  remains  of  the  leaf-system.  Glassworts  are  abundant  in 
salt  marshes  along  the  Atlantic  ocean  and  occur  at  various 
points  inland.  Such  leafless,  succulent  plants  seem  to  have  a 
peculiar  reason  for  reducing  their  evaporative  surface.  It  is 
not  on  account  of  the  scarcity  of  moisture,  as  in  the  instance 
of  the  cacti,  nor  of  surf,  to  which  bulrushes  are  adapted,  nor 
of  high  winds,  in  response  to  which  the  switch-plants  have  taken 


FIG.  120.    Glasswort.    After  Britton  and  Brown. 


260  Minnesota  Plant  Life. 

their  peculiar  forms;  but  rather  on  account  of  the  presence  in 
the  soil  of  salt  in  such  quantities  that,  if  the  plant  had  a  large 
evaporative  surface,  it  would  absorb  so  much  salt-water  from 
the  soil  to  meet  the  evaporation  that  its  tissues  would  become 
surfeited  with  saline  deposits. 

The  other  saline  plant,  known  as  the  western  blite,  occurs 
in  the  Red  river  valley,  in  the  region  of  Pembina  and  St.  Vin- 
cent. It  is  a  fleshy  herb,  with  thick  or  cylindrical  leaves  quite 
sessile  upon  the  twigs.  It  maintains  the  same  generally  suc- 
culent character  that  characterizes  the  glasswort,  but  has  not 
undergone  so  great  a  reduction  of  its  leaf-tract. 


FIG.  121.     Poke-weed.     After  Chesnut.     F.  B.  86,  U.  S.  Dept.  Ag. 

Russian  thistle.  Another  variety  of  pigweed,  not  native  to 
the  state,  but  introduced  in  large  numbers,  has  excited  a  great 
deal  of  attention  on  account  of  its  rapid  development  in  the 
wheat  fields  of  the  Red  river  valley.  This  is  the  Russian  thistle, 
a  tumbling  weed,  succulent  when  young,  but  turning  hard,  dry 
and  thorny  when  older.  A  variety  of  plant  very  similar  to  the 
Russian  thistle  is  found  along  the  Atlantic  seacoast.  It  has 
not,  however,  the  bushy  branches  of  the  thistle. 

Coxcombs.  The  amaranths  or  coxcombs  also  include  a  very 
common  tumbleweed  which  grows  in  globular  form,  two  or 


Minnesota  Plant  Life. 


261 


three  feet  across.  The  common  coxcombs  of  the  country 
flower-garden  are  relatives  of  this,  and  the  redroot  pigweed, 
a  familiar  barn-yard  plant,  is  another  closely  related  form.  Still 
another  amaranth  grows  flat  upon  the  ground  in  dooryards  and. 
along  the  roadside,  in  its  appearance  somewhat  resembling  purs- 
lane. 

Water-hemp.  The  water-hemp  which  grows  in  swamps  has 
flower  clusters  reminding  one  of  the  common  amaranth  of  the 
dooryard.  The  leaves  are  slender  and  willow-shaped,  while 
the  habitats  selected  by  the  plant  are  preferably  the  gravelly 
shores  of  lakes  or  rivers  in  the  southern  part  of  the  state. 

Pokeweeds.  The  poke- 
weed  family  is  represented 
in  Minnesota  by  a  single 
species  that  occurs  in  the 
southern  part  of  the  state 
rather  rarely.  In  this  plant 
the  fruit  is  a  black  berry 
with  from  five  to  fifteen 
chambers,  one  seed  in  each 
chamber.  The  root  is  poi- 
sonous, and  the  whole  plant 
has  a  strong,  unpleasant 
odor.  It  may  always  be 
recognized  by  the  division 
of  its  stem-pith  into  disks 
separated  from  each  other 
by  cavities. 

Four-o'clocks.  The  four-o'clocks  are  represented  by  three 
species  known  as  umbrella-worts,  and  remarkable  for  the  in- 
volucre which  stands  below  the  pink  or  reddish  flowers.  Three 
to  five  flowers  occur  in  a  single  circular  involucre  which,  when 
the  fruits  develop,  becomes  enlarged  and  papery.  The  flower- 
ing area  in  this  order  is  more  ornamental  than  that  of  former 
families ;  yet  there  are  no  petals,  the  colored  portion  being  of 
the  nature  of  calyx. 

Carpetweeds.  The  carpetweed  family  is  represented  in  Min- 
nesota by  the  common  carpetweed,  a  mat-plant  forming  pros- 
trate disks  of  vegetation,  made  up  of  the  much  branching,  flat, 


FIG.  122.     Carpetweed     After  Britton  and  Brown. 


262 


Minnesota  Plant  Life. 


plant-body.  The  leaves  are  in  whorls,  a  character  by  which 
this  plant  can  be  distinguished  from  other  mat-plants  of  waste 
fields.  The  flowers  are  small,  borne  in  the  axils  of  the  leaves, 
.and  without  petals.  The  carpetweed  grows  in  the  same  re- 
gions that  many  mat- 
grasses,  mat-knotweeds, 
purslanes  and  mat-spur- 
ges select. 

Purslanes  and  spring- 
beauties.  Of  the  purs- 
lanes three  genera  are  na- 
tive to  the  state :  the  com- 
mon purslane  or  "pus- 
ley,"  a  prevalent  weed  in  \ 
dooryards  and  gardens, 
the  rock  purslane,  ap- 
pearing upon  ledges  of 
granitic  rock  in  the  Min- 
nesota valley,  at  Taylor's 
Falls  and  at  Duluth,  and 
the  spring-beauties  or  Claytonias,  of 
which  there  are  three  varieties.  In 
the  state  there  are  two  species  of 
purslane :  the  common  garden  form 
with  leaves  round  at  the  end,  and 
the  notched  purslane  with  leaves 
notched  at  the  end.  The  latter 
plant  is  doubtless  a  native  of  Min- 
nesota, while  the  former  is  a  recent 
immigrant.  Purslane  is  one  of  the 
most  common  of  the  mat-plants  and 
is  remarkable  for  the  numerous 
flowers  which  it  produces  in  a  sea- 
son and  for  the  little  pods  which 
open  by  a  lid,  revealing  a  large 
number  of  small  seeds  within.  The  rock  purslane  is  a  dimin- 
utive herb  found  growing  in  the  crevices  of  granitic  or  eruptive 
rocks,  especially  in  the  Minnesota  valley  between  New  Ulm  and 
Big  Stone  lake.  The  stem  bears  at  the  base  a  few  alternate, 


FIG.  123.     Spring-beauty  in  flower. 
After  Atkinson. 


Minnesota  Plant  Life.  263 

almost  cylindrical  leaves,  from  among  which  rises  a  slender 
peduncle,  four  to  twelve  inches  high,  upon  which  the  small 
portulaca-like  flowers  are  arranged  in  flat-topped  clusters  or 
cymes. 

The  spring-beauties  are  succulent  herbs  with  delicate  flowers 
of  a  pinkish  color,  developed  in  terminal  cymes  on  short  slender 
stems.  In  two  of  the  species  the  roots  are  tuberous,  while  in 
the  third  they  are  fibrous.  In  each  flower  are  two  sepals,  five 
petals  and  five  stamens.  The  fruit  is  a  three-  to  six-seeded  cap- 
sule opening  by  three  clefts.  The  two  varieties  with  tuberous 
roots  may  be  distinguished  by  the  leaves  on  the  stem.  In  the 
ordinary  form  the  leaves  are  narrow  and  linear,  while  in  the 
rarer  variety  they  are  lance-shaped.  They  are  not  uncommon 
plants  in  the  southeastern  part  of  the  state,  flowering  in  spring. 

Corn-cockles,  chickweeds  and  carnations.  The  pink  family 
contains  about  twenty  five  Minnesota  species.  Herein  are  the 
corn-cockles,  the  campions  or  catchflies,  the  pinks,  the  soap- 
worts,  the  chickweeds,  the  stitchworts,  the  pearlworts  and  the 
sandworts  in  their  different  varieties.  The  plants  of  this  family 
are  all  small  herbs  with  opposite  entire  leaves,  both  sepals  and 
petals  present  and  a  single  ovary  ripening  into  a  capsule  or 
unopened  nut.  The  corn-cockles  are  not  native  to  the  state, 
but  have  been  introduced  into  the  wheat  fields  of  the  Red  river 
valley.  They  have  red  flowers  which  are  very  ornamental. 
The  catchflies  are  so  named  from  the  very  sticky  calyx  of  the 
flowers.  The  chickweeds,  sandworts  and  stitchworts  are  dimin- 
utive, generally  white-flowered  herbs  of  no  particular  impor- 
tance, but  rather  abundant  in  woods,  along  the  beaches  of  lakes 
and  in  low  places  on  the  prairies.  The  cultivated  pink  or  car- 
nation belongs  to  this  family,  and  while  its  flowers  are  doubled 
and  distorted  by  the  selection  which  has  been  given  to  them 
by  horticulturists,  yet  they  preserve  the  general  type  of  their 
family,  and  may  serve  as  comparative  plants  when  some  of  the 
wild  forms  are  under  investigation. 

All  the  families  of  the  fourteenth  order  unite  in  one  pecu- 
liarity, that  of  having  the  embryo  in  the  seed  coiled  around  the 
albumen.  In  some  seeds  the  embryo  is  curved  almost  like  a 
snail-shell,  while  in  others  it  is  not  bent  more  than  a  horseshoe. 
The  albumen  lies  inside  the  coils  of  the  embryo,  which  are 


264 


Minnesota  Plant  Life. 


appressed  to  the  seed-coat  layers.  The  lower  families  of  the 
order  are  devoid  of  perianth,  while  in  the  higher  families,  such 
as  the  pinks,  both  calyx  and  corolla  are  well  developed. 

Almost  all  the  families  hitherto  mentioned — with  the  ex- 
ception of  the  pinks  and  portulacas — are  characterized  by  the 
quite  general  failure  of  the  flowers  to  develop  two  kinds  of 
perianth  leaves.  When  only  one  layer  or  whorl  of  perianth 
leaves  is  present  in  the  flower,  this  group  of  parts  is  regarded 
as  the  calyx,  hence  the  great  majority  of  plants  in  the  families 
that  have  been  under  examination  are  considered  to  be  devoid 
of  petals.  In  the  remaining  families  both  calyx  and  corolla  are 

for  the  most  part  present,  al- 
though there  are  numerous 
exceptions,  especially  in  the 
lower  families  of  the  series. 
The  fifteenth  order  in- 
cludes the  water-lily  family 
and  a  curious  little  related 
plant  known  as  the  horn- 
wort,  also  of  aquatic  habit. 
Here,  too,  is  placed  the  \vell- 
known  crowfoot  family,  to 
which  the  anemones,  lark- 
spurs, peonies,  buttercups, 
aconites,  columbines,  marsh- 
marigolds  or  crocuses,  gold- 

Fm.124.    Water-shield.     After  Britton  and  Brown,     threads,      mCadoW-FllCS      and 

clematis     belong.     In    this 

order,  also,  are  included  the  barberries  and  their  allies,  the  moon- 
seeds,  the  magnolias,  the  pawpaws,  the  laurels  and  a  few  small 
exotic  families  not  represented  in  the  United  States. 

Water-shields.  The  water-lilies  in  their  various  forms  are 
familiar  inhabitants  of  the  lakes  and  ponds  for  which  Minne- 
sota is  so  justly  famous.  There  are  a  number  of  varieties, 
some  more  common  than  others.  One  of  the  most  inter- 
esting is  the  water-shield,  which  alone  has  perfectly  shield- 
shaped  leaves  that  always  float  upon  the  surface  of  the  water. 
The  leaves  of  the  Indian  lotus  are  also  truly  shield-shaped; 
however,  many  of  them  do  not  float  upon  the  top  of  the  water, 


Minnesota  Plant  Life. 


265 


but  rise  above  it.  Besides,  the  leaves  of  the  water-shield  are 
oval  and  not  more  than  four  inches  in  length,  while  those  of 
the  lotus  are  circular  and  much  larger.  Water-shield  flowers 
are  purple,  less  than  an  inch  in  diameter,  and  the  whole  plant 
is  easily  distinguished  from  any  other  kind  of  water  vegetation 
that  might  be  mistaken  for  it  by  a  very  abundant  deposit  of 
transparent  jelly  over  the  stems,  buds,  flower  pedicels  and  the 
under  sides  of  the  leaves.  The  leaves  are  commonly  purple 


FIG.  125.     Water-lilies.    After  photograph  by  Williams. 

below  and  dark  green,  shaded  with  purple  above.  The  pres- 
ence of  the  purple  dye  on  the  under  sides  of  floating  leaves 
is  not  uncommon.  It  will  be  found  to  some  extent  in  water- 
lily  and  pond-lily  leaves  and  in  the  leaves  of  the  floating  pond- 
weed.  The  purple  substance  is  a  heat-producing  color,  and 
apparently  such  sunlight  as  the  plant  does  not  utilize  in  starch- 
making  may  be  converted  into  heat  by  the  lower  layers  of  the 
leaf  and  employed  as  a  source  of  energy  in  various  growth- 
processes  of  the  plant.  The  stem  of  the  water-shield  is  some- 


266  Minnesota  Plant  Life. 

times  several  feet  in  length,  and  it  creeps  at  the  bottom  of  the 
pond  as  a  slender  rootstock.  In  the  flower  there  are  from 
twelve  to  twenty  stamens  and  from  four  to  eighteen  carpels, 
separate  from  each  other,  forming  in  the  fruit  a  cluster  of  one 
or  two-seeded  nuts. 

Pond-lilies.  The  pond-lilies  may  be  known  by  their  broadly 
arrow-shaped  leaves  with  rounded  bases,  their  yellow  flowers, 
and  their  fruits,  consisting  of  a  number  of  carpels  united  to- 
gether in  a  compound  body.  There  are  two  varieties  in  Min- 
nesota :  the  common  yellow  pond-lily,  abundant  throughout  the 
state,  and  the  small  yellow  pond-lily,  of  which  the  flowers  are 
less  than  an  inch  in  diameter  when  open.  The  latter  species 
is  limited  to  the  northern  district  between  Duluth  and  Lake  of 
the  Woods.  The  pond-lilies  have  thick  cylindrical  rootstocks, 
which  show  conspicuous  scars  where  the  leaves  break  off.  In 
the  large  pond-lily  there  are  sometimes  submerged  leaves  which 
are  thin  and  almost  circular  in  shape.  These  submerged  leaves 
are  always  present  in  the  smaller  pond-lily. 

Water-lilies.  The  water-lilies,  of  which  three  species  occur 
in  the  state,  may  be  recognized  by  their  white  flowers,  rounder 
leaves  and  almost  globular  fruit.  The  form  known  as  the  tuber- 
bearing  lily  is  probably  more  common  than  the  sweet-scented 
lily,  though  both  are  found  growing  side  by  side  in  the  same 
ponds.  In  the  tuber-bearing  lily  the  rootstock  is  thick,  with  an 
abundant  production  of  short  lateral  branches  that  readily  sep- 
arate and  serve  to  propagate  the  plant.  In  the  sweet-scented 
lily  the  rootstock  is  thick  and  but  sparingly  branched.  Fur- 
thermore, the  flowers  of  the  sweet-scented  lily  are  very  fragrant, 
while  those  of  the  tuber-bearing  lily  are  either  scentless  or  but 
slightly  fragrant.  These  two  varieties  are  the  abundant  ones. 
In  a  few  lakes  along  the  international  boundary  may  be  found 
the  small  white  water-lily,  with  its  flowers  scentless  and  scarcely 
two  inches  wide.  In  this  variety  the  petals  are  generally  in 
but  two  rows  instead  of  being  disposed  in  numerous  whorls  as 
in  the  common  forms.  The  leaves  are  considerably  smaller 
but  of  the  same  general  shape. 

The  great  pale  rootstocks  of  the  water-lilies  and  pond-lilies 
are  often  torn  up  by  the  ice  and  cast  ashore  in  early  spring. 


Minnesota  Phnt  Life.  267 

They  are  spongy,  and  when  released  from  the  bottom  of  the 
lake  float  to  the  surface. 

Indian  lotus.  The  largest  flowered  and  most  interesting  of 
the  native  water-lilies  is  the  Indian  lotus — not  very  frequent  in 
Minnesota,  and  confined  to  a  few  localities.  It  occurs  in  the 
Mississippi  river  at  Red  Wing,  Mendota  and  La  Crosse;  also 
in  Lake  Pepin  and  at  the  extreme  north  end  of  Halstead's  bay, 
Lake  Minnetonka.  The  leaves  are  shield-shaped  with  central 
stem,  and  from  one  to  two  feet  broad.  Some  of  them  are  raised 
above  the  water  and  become  slightly  vase-shaped,  while  others 
float  upon  the  surface.  The  flowers,  which  may  be  ten  inches 
in  diameter,  though  not  commonly  reaching  this  size,  are  of  a 
pale  cream-color,  and  differ  from  those  of  the  other  water  lilies. 
The  fruiting  area  is  quite  remarkable.  The  top  of  the  flower 
stem  is  flattened  out  into  a  biscuit-shaped  body  in  which  the 
little  nuts,  the  size  of  an  acorn,  are  imbedded.  They  loosen 
as  the  fruit  matures  and  rattle  about  so  that  the  lotus  in  some 
districts  goes  by  the  name  of  "rattlebox."  This  plant  belongs 
to  the  same  genus  in  which  the  famous  lotus  of  the  Nile  and 
the  Orient  is  classified.  The  true  oriental  lotus  is  also  known 
in  the  east  as  Indian  lotus  because  it  grows  in  India.  Such  a 
fact  is  illustrative  of  the  confusion  that  sometimes  arises  when 
only  popular  names  are  employed  in  the  designation  of  plants. 

The  water-lilies,  like  very  many  aquatic  flowering  plants,  dis- 
play their  flowers  at  the  surface  of  the  water,  and,  after  pollina- 
tion has  been  effected,  close  the  flower  into  a  bud  again  and 
retract  it  beneath  the  surface,  ripening  the  seeds  beyond  the 
reach  of  aerial  dangers.  The  lotus,  however,  ripens  its  fruits 
in  the  air. 

Hornworts.  The  hornworts  are  apparently  very  rare  plants 
in  Minnesota,  but  are  known  to  grow  in  the  vicinity  of  St.  Paul 
and  Minneapolis — in  White  Bear  lake  and  Lake  Calhoun ;  and  in 
the  western  part  of  the  state — in  Lakes  Osakis  and  Alexandria. 
They  are  submerged  plants  with  slender  stems,  and  the  leaves 
are  arranged  in  whorls  and  are  finely  dissected  into  thread-like 
filaments.  The  flowers  are  produced  singly  in  the  axils  of  the 
leaves  and  are  less  than  half  an  inch  in  length.  There  are 
numerous  stamens  in  each  staminate  flower,  while  the  pistillate 
flower  develops  a  single  one-chambered  ovary,  containing  a 


268 


Minnesota  Plant  Life. 


solitary  seed  rudiment.  The  fruit  is  like  a  miniature  lotus  nut. 
There  is  no  albumen,  and  the  embryo  is  remarkable  for  having 
four  seed  leaves  instead  of  two.  This,  however,  may  be  re- 
garded as  due  to  a  forking  of  the  seed  leaves  as  they  develop. 

Magnolias.  Magnolias  do  not  occur  in  Minnesota.  Their 
flowers  are  very  much  like  those  of  the  water-lilies,  and  they 
may  be  regarded  as  terrestrial,  tree-like  water-lilies,  or  con- 
versely, water-lilies  might  be  considered  as  magnolia-like  plants 
which  at  an  early  time  went  into  the  water  and  adapted  them- 
selves to  the  aquatic  life.  Re- 
lated to  the  magnolias  are  the 
tulip-trees  or  whitewoods  which 
are  such  noble  forms  in  the  for- 
ests of  Indiana  and  Ohio. 

The  pawpaws,  abundant  south- 
ward, constitute  a  family  of  the 
fifteenth  order,  but  are  not  known 
to  occur  so  far  north  as  Minne- 
sota. 

Crowfoots.  The  crowfoot 
family  is  abundantly  represented 
in  Minnesota  where  there  are  to 
be  found  one  species  of  golden 
root,  two  of  marsh-marigolds, 
one  of  goldthread,  one  of  false 
rue-anemone,  two  baneberries, 
the  red  and  the  white,  one  colum- 
bine, three  larkspurs,  seven  or 
eight  anemones,  two  hepaticas, 

one  rue-anemone,  one  pasque  flower  or  gosling,  two  clematises, 
one  mousetail,  twenty  buttercups  and  their  allies,  and  three 
meadow-rues.  Many  of  these  are  common  flowers  of  the  spring 
and  summer.  The  marsh-marigolds,  termed  also  crocuses,  are 
abundant  throughout  the  state,  their  yellow  flowers  blooming 
in  early  spring.  A  peculiar  form,  known  as  the  floating 
marsh-marigold,  occurs  among  the  northern  lakes.  It  is  much 
like  the  ordinary  variety  except  that  its  leaves  float  upon  the 
surface  of  the  water  and  the  plant  is  generally  small.  The 
goldthreads  are  little  three-leaved  plants  with  white,  buttercup 


FIG.  126.     Marsh-marigold  or  cowslip. 
After  Britton  and  Brown. 


Minnesota  Plant  Life.  269 

flowers  and  slender,  bright  yellow  rootstocks,  by  which  they 
may  be  recognized.  They  are  abundant  in  tamarack  swamps. 
The  baneberries  are  erect  herbs  with  large  compound  leaves. 
The  flowers  are  small,  white  and  arranged  in  terminal  racemes. 
One  variety  produces  red  berries  and  the  other  white.  The 
columbines  are  particularly  abundant  upon  rocky  hillsides,  on 
cliffs  and  along  river  gorges.  The  flowers  are  recognized  at 
once  by  the  spurs  on  the  petals,  and  stand  with  their  mouths 
directed  downward.  The  spurs  are  supplied  with  honey  glands 
at  the  tip,  and  the  whole  contrivance  is  a  machine  for  obtaining 
cross-pollination  through  the  agency  of  insects. 

Larkspurs.  The  larkspurs  are  the  first  type  of  two-sided 
flowers  that  have  been  encountered  in  the  discussion  of  plants 
with  pairs  of  seed-leaves.  Their  flowers  stand  in  terminal  clus- 
ters, are  loosely  arranged  and  shaped  so  that  there  is  no  diffi- 
culty, even  when  they  are  separated,  in  determining  how  they 
stood  upon  the  stem.  One  of  the  petals  is  provided  with  a  spur 
as  in  the  columbines.  This  again  is  an  apparatus  to  utilize  some 
insect  for  the  advantage  of  the  plant. 

Anemones  and  Hepaticas.  Anemones  are  herbs  with  rather 
characteristic  flowers  and  fruit-bodies.  In  one  type  the  nutlets 
of  the  fruit  are  massed  in  cylindrical  clusters,  clothed  with 
woolly  hairs.  In  others  the  clusters  of 'nutlets  are  more  nearly 
spherical.  Closely  related  to  the  anemones  are  the  Hepaticas, 
known  by  their  three-lobed,  shining  leaves  and  their  purplish 
flowers  put  forth  in  early  spring.  One  kind  of  Hepatica  has  its 
leaves  rather  round-pointed  while  the  other  shows  much  sharper 
lobes.  Akin  to  the  Hepaticas  is  the  rue-anemone,  which  devel- 
ops three-parted  leaves,  each  lobe  of  which  is  again  divided  into 
three.  The  stem,  four  to  seven  inches  in  height,  arises  from  a 
little  cluster  of  small  tuberous  roots  shaped  like  diminutive  beets. 
This  plant  may  be  distinguished  from  the  false  rue-anemone, 
which  resembles  it  superficially  to  a  marked  degree,  by  the 
character  of  the  tuberous  roots.  In  the  false  rue-anemones  the 
tubers  do  not  form  a  little  cluster  near  the  base  of  the  stem,  but 
develop,  in  many  instances,  two  or  three  of  them  on  the  same 
root  and  often  some  distance  from  the  base  of  the  stem.  Be- 
sides, the  fruits  of  the  true  rue-anemone  are  aggregated  as 
nutlets  at  the  tip  of  the  fruiting  stem,  while  in  the  false  the 


270 


Minnesota  Plant  Life. 


fruits  are   not   strictly  nuts  but   capsules,   opening  along  one 
side  to  release  the  seeds.     There  are  several  seeds  in  each  cap- 


£.5 
Si 


sule  of  the  false  rue-anemone,  but  only  one  seed  in  each  nutlet 
of  the  true.  Both  plants  are  abundant  in  the  woods  through- 
out the  state. 


Minnesota  Plant  Life. 


Pasque  flowers  and  clematis.  The  pasque  flower  or  gosling 
is  known  to  the  children  of  Minnesota  as  the  first  flower  to 
bloom  in  early  spring.  There  are  several  kinds  of  flowers  which 
really  open  before  the  pasque-flower,  but  they  are  either  rare 
or  inconspicuous,  so  that  the  pasque  flower  may  be  popularly 
regarded  as  the  earliest  flower  of  the  year.  The  sepals  are  of 
a  pretty  light  purple  color,  and  the  whole  flower  is  an  inch  or 
more  across.  Around  its  base  is  a  group  of  hairy  involucral 
leaves.  At  the  center  is  a  circle  of  separate  carpels  which  ma- 
ture into  a  head  of  nutlets,  each 
of  which  has  a  long  plume-like 
appendage,  recalling  the  similar 
structures  in  the  fruiting  heads 
of  clematis.  In  this  latter  plant, 
which  in  Minnesota  occurs  as  a 
climbing  vine,  the  same  general 
appearance  of  the  fruiting  heads 
is  to  be  observed,  and  conse- 
quently the  pasque  flower  is  also 
termed  the  ground-clematis.  The 
true  clematises  are  not  always 
climbing  vines  throughout  the 
United  States,  but  the  Minnesota 
varieties  both  belong  to  the  vine 
division  of  the  genus.  They  have 
an  odd  way  of  climbing,  for,  not 
being  provided  with  true  ten- 
drils, they  twine  their  leaves 
around  such  supports  as  come  in 

their  way,  thus  using  the  stems  of  the  leaves  just  as  a  squash 
vine  uses  its  tendrils.  This  habit  of  the  clematis  gives  an  idea 
of  how,  in  some  instances,  tendrils  may  have  originated.  After 
the  leaves  of  a  plant  acquired  the  habit  of  turning  themselves 
about  twigs  or  other  supports  that  came  in  their  way,  there 
arose  a  division  of  labor,  in  consequence  of  which  some  leaves 
devoted  themselves  to  their  new  function  and  gradually  aban- 
doned their  starch-making,  thus  becoming  converted  into  true 
tendrils,  while  others  assumed  no  tendril  functions,  but  contin- 
ued as  the  starch-makers  of  the  plant. 


FIG.  128.     White  water-buttercup. 
Britton  and  Brown. 


After 


272 


Minnesota  Plant  Life. 


Mousetails.  The  mousetail  is  a  little  herb  three  or  four 
inches  in  height,  known  to  occur  in  the  extreme  southwestern 
part  of  the  state.  The  center  of  the  flower  is  prolonged  into 
a  spike-like  axis  upon  which  the  nutlets  are  arranged  in  spirals. 
From  the  resemblance  of  this  axis  or  receptacle  of  the  flower, 
to  the  tail  of  a  mouse  has  arisen,  the  common  name. 

Buttercups.  Buttercups  are  well-known  plants,  usually  with 
yellow  flowers  by  which  they  may  be  distinguished  from  anem- 
ones, the  flowers  of  which  are  pale.  There  are  a  number  of 
sorts  characterized  by  the  different  forms  of  the  leaves,  the  sizes 

of  the  flowers  and  the  shapes 
of  the  nutlets  or  groups  of 
nutlets  in  the  fruiting  state. 
Three  buttercups  in  the 
United  States  are  aquatic, 
and  two  of  these  occur 
abundantly  in  Minnesota. 
Owing  to  their  aquatic  habit 
the  water-buttercups  have 
finely  dissected  leaves  con- 
sisting of  thread-like  fila- 
ments, and  their  flowers  are 
white.  The  two  varieties 
may  be  distinguished  from 
each  other  by  the  rigidity 
of  their  stems  when  with- 

FIG.  129.     Early  meadow-rue.     After  Britton  and     c[rawn  from  the  water.      The 
Brown. 

white  water-buttercup  col- 
lapses into  a  flabby  bundle  when  lifted  from  the  water,  while 
the  stiff  water-buttercup  does  not,  but  maintains  the  ends  of  its 
stems  in  a  rigid  position.  The  water-buttercups  are  interesting 
plants  to  observe  on  account  of  the  automatic  curvatures  of  the 
flowering  pedicels.  The  flowers  are  exposed  above  the  sur- 
face of  the  water  and  after  pollination  the  stems  bend  over,  as 
if  aware  of  what  was  needed,  and  thrust  the  flowers  into  the 
water,  so  that  the  fruits  are  matured  below  the  surface.  Such 
beneficial  habits  are  ordinary  among  water  plants,  which  are 
generally  compelled  to  expose  their  flowers  for  wind  or  for  in- 
sect pollination,  but  afterwards  derive  advantage  from  ripening 


Minnesota  Plant  Life.  273 

their  fruits  under  less  dangerous  conditions.  Thus  the  flowers 
of  the  water-lilies,  of  the  pondweeds,  or  of  the  eel-grass  are  in 
a  variety  of  ways  retracted.  What  the  eel-grass  secured  by  a 
spiral  contraction  of  the  flowering  stem  is  accomplished  by  the 
water-buttercup  through  an  automatic  curvature.  Such  curv- 
atures are  sometimes  employed  by  terrestrial  varieties  for  the 
insertion  of  their  fruits  into  the  soil.  Thus  the  peanut  plant 
flowers  above  the  ground  and  then  thrusts  its  young  pods  into 
the  soil,  where  they  mature  underground. 

Meadow-rues.  The  meadow-rues  are  robust  perennial  herbs 
with  leaves  compounded  repeatedly  on  the  plan  of  three.  The 
flowers  are  small,  whitish-green  and  aggregated  in  large  pan- 
icles or  racemes.  In  one  variety,  the  most  common  in  Minne- 
sota, there  are  two  sorts  of  flowers,  staminate  and  pistillate, 
borne  on  different  plants,  so  that  all  the  flowers  on  a  plant  will 
be  of  one  kind  or  the  other.  The  other  two  species  have  each 
on  the  same  plant  three  kinds  of  flowers,  some  producing  only 
stamens,  others  producing  only  pistils,  and  others  in  which 
both  stamens  and  pistils  occur.  One  variety  is  often  glandular 
or  waxy  in  the  texture  of  its  leaves,  while  the  other  is  smooth  or 
slightly  hairy,  but  not  glandular  or  waxy.  The  former  blooms 
earlier  than  the  latter  and  is  usually  shorter,  reaching  in  favor- 
able positions  three  to  seven  feet  in  height,  while  the  latter 
attains  a  height  of  from  ten  to  eleven  feet.  Although  the 
species  in  which  the  flowers  are  always  separated,  and  a  single 
plant  produces  only  one  kind,  is  easily  identified,  the  other  two 
are  hard  to  distinguish. 

Most  of    the  plants  in  the  crowfoot    family  have  pungent 
juices,  and  from  some  of  them  highly  poisonous  substances,  such 
as  aconite,  are  obtained. 
19 


Chapter  XXIX. 

From  Barberries  to  Witch-hazels. 


Barberries.  The  three  plants  of  the  barberry  family  which 
occur  in  Minnesota  are  of  quite  different  appearance.  One,  the 
common  barberry,  introduced  from  Europe,  grows  as  a  wild 
plant  in  the  southern  part  of  the  state,  but  is  by  no  means 
abundant.  It  is  a  smooth  shrub  with  ovate  saw-tooth-mar- 
gined leaves  and  flowers  produced  on  drooping  racemes  in  the 
axils  of  some  the  leaves.  The  flowers  are  yellow  and  unpleas- 
antly scented.  The  fruit  clusters  are  racemes  of  scarlet  sour 
berries,  somewhat  oblong  in  shape  and  about  half  an  inch  in 
length.  Many  of  the  leaves  are  reduced  to  three-pronged  thorns. 
This  is  the  plant  which  is  famous  as  the  host  of  the  cluster-cup 
stage  of  the  wheat  rust,  and  for  this  reason  it  is  a  dangerous 
shrub  to  cultivate.  The  other  members  of  the  barberry  family 
are  herbs.  One  of  them,  the  blue  cohosh,  is  found  in  shaded 
woods,  growing  a  foot  or  more  in  height  and  resembling,  to 
some  extent,  the  meadow-rue.  But  when  the  cohosh  fruits 
it  produces  clusters  of  blue  berries  which  are  in  reality  seeds, 
for  they  burst  the  thin  fruit  wall  when  young  and  mature 
outside  of  it.  The  other,  known  as  the  may-apple  or  wild 
mandrake,  has,  at  the  base,  large  shield-shaped  leaves  almost  a 
foot  in  diameter,  while  the  upper  leaves  are  deeply  lobed,  lighter 
green  above  than  below.  The  flowers  are  white,  somewhat 
butercup-like,  nodding  from  the  axils  of  the  leaves  and  one  or 
two  inches  wide.  A  true  fleshy  berry  of  a  yellow  color  is  pro- 
duced, two  inches  long  and  edible.  This  plant  occurs  in  damp 
woods  along  the  flood  plains  of  streams  flowing  into  the  Mis- 
sissippi, in  the  extreme  southeastern  portion  of  the  state. 

Moonseeds.  The  moonseeds,  represented  in  Minnesota  by 
a  single  form,  are  characterized  by  the  disk-shaped  or  coin- 
shaped  seeds,  hence  the  popular  name.  The  Minnesota  moon- 


Minnesota  Plant  Life. 


275 


seed  is  a  common  vine,with  leaves  shaped  a  little  like  the  leaves  of 
the  wild  grape,  though  not  so  deeply  angled.  The  underground 
portion  is  yellow  and  Indians  use  it  for  medicine.  The  flowers 
are  of  two  sorts,  developed  on  different  plants.  The  fruit  con- 
tains a  stone  which  is  curved  into  a  circle,  marked  by  clefts  and 
strongly  flattened  on  the  sides.  The  bunches  of  fruits  are  blu- 
ish-black in  color  and  resemble 
a  little  the  fruits  of  the  wild 
grape.  They  are  easily  distin- 
guished, however,  by  the  pres- 
ence in  each  of  the  flat  stone, 
very  different  from  the  pear- 
shaped  seeds  which  are  found 
in  the  berries  of  the  grape. 
Calycanthuses  and  laurels,  where  the  sassafras, 
bays  and  spice-bushes  are  grouped,  do  not  pro- 
duce any  Minnesota  varieties. 

The  sixteenth  order  includes  the  poppy  fam- 
ily, where  the  blood-roots,  Dutchman's  breeches 
and  fumitories  are  classified;  the  mustards, 
among  which  may  be  mentioned  the  water 
cresses,  rock  cresses,  whitlow-grasses,  pepper- 
grasses  and  shepherd's  purses ;  the  caper  family, 
with  the  clammy-weeds  and  spider-flowers;  the 
mignonettes,  and  two  other  families  not  repre- 
sented in  the  United  States. 

Blood-roots.  Besides  the  common  poppy, 
which  in  some  parts  of  the  state  has  escaped 
from  cultivation,  the  blood-root  is  a  common 
form  throughout  the  greater  portion  of  Minne- 
sota. Blood-root  flowers  are  to  be  seen  in  the 
spring  in  open  woods,  where  their  white  petals 
and  great  abundance  make  them  attractive  ob- 
jects. The  plant  is  named  from  the  red  juice 
which  exists  in  its  horizontal  underground  rootstock.  On  the 
latter,  branches  arise,  bearing  leaves— those  at  the  base  scale- 
shaped  and  the  upper  ones  large,  heart-shaped  or  kidney- 
shaped,  with  several  lobes.  The  flowering  stem  displays  usually 
but  a  single  flower  in  which  there  are  two  sepals  that  early  fall 


FIG.  130.  May-ap- 
ple,or  mandrake, 
in  flower.  After 
Atkinson. 


FIG.  131.     Clammv-weed.     After  Britton  and  Brown. 


276  Minnesota  Plant  Life. 

to  the  ground.  The  pet- 
als, eight  to  twelve  in 
number,  inclose  the  nu- 
merous stamens.  At  the 
center  the  rudimentary 
fruit  appears  as  an  ob- 
long, narrow,  one-cham- 
bered pod,  made  up  of 
two  carpels  and  ripening 
into  a  .capsule  with  nu- 
merous seeds.  The  later 
leaves  of  the  year  grow 
much  larger  than  those 
formed  at  the  time  of 
flowering  and  by  their  ac- 
tivity create  considerable 
reserve  food  material 
which  is  packed  away  in 

the  underground  part  ready  for  use  by  the  buds  of  the  next 
season. 

Dutchman's-breeches.  The  Dutchman's-breeches  or  squirrel- 
corn,  of  which  two  species  occur 
in  Minnesota,  are  delicate  and  in- 
teresting plants  of  the  woodland, 
where  they  grow  on  shaded 
banks.  The  leaves  are  com- 
pounded repeatedly  on  the  plan 
of  three  and  the  slender  flowering 
stem  bears  several  nodding  flow- 
ers flattened  laterally  in  a  peculiar 
manner.  The  shape  of  the  flower 
gives  occasion  for  the  common 
name.  Below  the  ground,  in  the 
Dutchman's-breeches,  a  number 
of  bulbous  scales  may  be  discov- 
ered. When  fresh  they  are  speck- 
led with  red  dots.  In  the  squir- 
rel-corn, the  flowers  of  which  are 
not  so  bifurcated  as  those  of  the 


FIG.  132.    Blood-root.    After  Britton  and 
Brown. 


Minnesota  Plant  Life. 


277 


Dutchman's-breeches,  the  slender  rootstocks  bear  a  number  of 
little  spherical  tubers.  The  common  bleeding-heart  of  flower- 
gardens  is  a  relative  of  these  two  native  species. 

Fumitories.  The  fumitories,  with  yellowish  or  pinkish,  two- 
sided  flowers,  occur  in  Minnesota  in  four  different  forms.  Among 
the  more  common  is  the  pale  fumitory  with  whitish-green  leaves 
compounded  on  the  plan  of  three.  This  plant  is  most  abun- 
dant in  the  northern  part  of  the  state,  where  it  grows  often  on 
sandy  beaches.  The  golden  fumitory,  frequent  in  the  southern 
part  of  the  state  along  railway  embankments  and  in  woods,  is 
a  smaller,  darker  green  plant,  with  golden  yellow  flowers  ar- 

ranged in  terminal  ra- 
cemes. Another  variety, 
the  yellow,  not  so  com- 
mon as  the  golden  fumi- 
tory, may  be  recognized 
by  its  paler  leaves,  like 
those  of  the  pink-flow- 
ered northern  form;  but 
this  species  has  yellowish 
flowers,  not  so  bright  as 
those  of  the  golden  fumi- 
tory, and  quite  different 
from  the  pinkish  type  of 
the  pale  fumitory.  Still 
another,  found  at  the  ex- 
treme southern  edge  of 


FIG.  133.     Water-cress.     After  Britton  and  Brown. 


111  11  C 


smaller  flowers  than  the  others  and  foliage  much  like  that  of 
the  pink  species. 

Mustards.     The  mustard  family  is  distinguished,  for  the  mos 
part,  by  a  pungent  peppery  sap,  so  that  after  one  has  tasted 
water-cress  or  pepper-grass  he  can  usually  determine,  by  c 
ing  the  foliage,  the  relationship  of  other  plants  of  the  fam 
A  variety  of  mustards  occur  in  Minnesota,  about  fifty  spe 
in  all.     Besides  this,  several  are  cultivated,  such  as  the  cabl 
the  cauliflower,  the  radish  and  the  turnip.     Mustards  are  : 
ognized  botanically  by  their  pods,  flattened  lengthwise  or  en 
wise  to  the  partition  which  runs  along  them.     In  some  po 


278 


Minnesota  Plant  Life. 


the  partition  is  evanescent,  as  in  the  garden  radishes.  Very 
common  forms  are  the  pepper-grasses  with  little  circular  pods, 
the  shepherd's  purses  with  heart-shaped  pods,  the  hedge-mus- 
tards with  their  long  and  slender  pods,  the  rock-cresses  grow- 
ing upon  cliffs  and  along  gorges,  the  water-cress  abundant  in 
cold  streams  issuing  from  springs,  and  the  other  cresses,  some 
in  the  fields,  some  in  the  woods  and  others  in  marshes  or 
swamps.  In  a  great  many  of  the  mustards  of  Minnesota  the 
leaves  are  narrow  and  deeply  lobed  along  the  sides.  A  number 
bear,  at  the  surface  of  the  ground, 
rosettes  of  leaves  from  which  the 
slender  flower-bearing  axis  arises. 
The  flowers  are  usually  arranged  in 
racemes  and  are  commonly  white 
or  yellow  in  color,  constructed  on 
the  plan  of  four.  Four  sepals,  four 
petals,  six  stamens  and  two  carpels, 
united  into  a  single  pod,  constitute 
the  parts  of  the  normal  mustard 
flower.  One  of  the  smallest  of  the 
land-flowering  plants  in  Minnesota 
is  the  whitlow-grass,  a  cress  which 
produces  a  tiny  rosette  of  leaves  and 
a  little  stem  an  inch  or  two  in 
height,  on  which  a  few  minute  white 
flowers  are  borne. 

Pitcher-plants.     The  seventeenth 
order    includes    the    pitcher-plants,    FlG- 134-   etcher-plant.  After  Britton 

and  Brown. 

grouped  in  two  families,  to  one  of 

which  belongs  a  common  Minnesota  variety,  and  the  sundews 
and  Venus'  fly-traps.  All  of  these  plants  are  carnivorous  and 
are  very  remarkable  for  the  skillful  devices  by  which  they  catch 
the  insects  that  form  a  part  of  their  food.  The  Venus'  fly-trap, 
which  in  conservatories  is  sometimes  cultivated,  from  its  Car- 
olina home,  is  a  little  herb  with  leaves  built  upon  the  general 
plan  of  a  steel  trap.  The  base  of  the  leaf  is  somewhat  elongated 
and  provided  with  wings  of  green  tissue.  Above  the  middle 
there  is  a  strong  constriction,  and  the  end  of  the  leaf  is  almost 
round,  with  a  longitudinal  rib  separating  it  into  two  halves. 


Minnesota  Plant  Life. 


279 


On  the  upper  side  are  some  sharp-pointed  hairs,  and  when  an 
insect  alights  upon  a  leaf  and  irritates  the  hairs  a  couple  of  times 
the  two  sides  of  the  leaf  snap  together  with  a  movement  suffi- 
ciently sudden  to  catch  the  insect,  after  which  its  body  is  di- 
gested by  the  plant.  A  little  less  sensational  but  none  the  less 
accurate  are  the  fly-catching  habits  of  the  common  Minnesota 
pitcher-plant  which  grows  in  abundance  throughout  the  tama- 
rack swamps  of  the  state.  The  leaves  of  this  plant  are  hol- 
lowed out  as  vase-like  structures,  and  are  usually  half  full  of 
water.  The  margin  of  each  pitcher  is  protected  by  a  flap  on 
which  are  arranged  a  number  of  hairs  pointing  downwards. 
Within,  the  surface  of  the  pitcher  is  very  smooth.  Inquisitive 
insects  which  alight  upon  the  flap  find  it  easy  to  walk  in  the 
direction  in  which  the  hairs  are  pointed,  but  difficult  to  move 
in  the  other  direction.  Thus  they  are  guided  to  the  smooth 
rim  of  the  vase  and  tumble  in.  Digestive  ferments  are  secreted 
by  the  action  of  glands  or  of  bacteria  which  inhabit  the  water 
in  the  pitcher,  and  the  bodies  of  the  insects  are  converted  into 
food-material  for  the  bacteria,  and  directly  or  indirectly  find 
their  way  into  the  tissues  of  the  pitcher-plant  itself.  The  flower 
of  the  pitcher-plant,  standing  on  its  slender,  erect  stalk,  is  con- 
spicuous by  its  purplish  petals  and  by  a  very  extraordinary  um- 
brella-shaped stigma  which  arches  over  the  short  stamens,  pro- 
tecting their  sensitive  pollen-spores  from  the  cold  of  the  bog 
where  these  plants  select  their  abode.  Besides,  this  umbrella- 
shaped  stigma  serves  as  preventive  against  the  flower  being 
pollinated  by  its  own  pollen.  The  pollen  spores  germinate  on 
the  points  at  the  angles  of  the  umbrella.  The  fruit  is  made  up 
of  five  fused  carpels  and  contains  numerous  small  seeds. 

Sundews.  Related  to  the  pitcher-plants  are  the  sundews, 
which  are  found  throughout  the  state  in  deep  tamarack  swamps 
or  peat-bogs.  There  are  four  varieties,  distinguished  by  the 
shapes  of  their  leaves,  to  be  looked  for  in  Minnesota.  The 
round-leafed  sundew  is  as  common  as  any.  In  this  the  leaves 
are  almost  round,  on  slender  stems,  spreading  out  in  a  little 
circle  at  the  base  of  the  delicate,  erect  flowering  axis.  The 
leaves  are  half  an  inch  or  so  broad  and  covered  over  with  prom- 
inent red  glandular  hairs.  Another  variety  has  the  leaves  ovate 
or  spoon-shaped.  In  still  another,  the  leaves  are  long-ovate, 


280 


Minnesota  Plant  Life. 


four  or  five  times  as  long  as  broad,  while  in  yet  another  the 
leaves  are  shaped  almost  like  grass  leaves,  one  to  three  inches 
long  and  slightly  spoon-shaped  toward  the  tip.  In  all  the  dif- 
ferent species  the  glandular  hairs  are  present.  When  a  small 
insect  alights  upon  one  of  the  leaves  the  sticky  secretions  of 
the  hairs  interfere  with  its  movements,  while  the  hairs  at  the 
edge  of  the  leaf  bend  inward  and  push  the  insect  down  into  a 
helpless  position.  The  whole  leaf  then  seems  to  close  around 
the  unfortunate  ant  or  fly,  and  after  a  time,  by  means  of  di- 
gestive ferments,  its  body  is  converted  into  nutriment  for  the 
plant.  In  Portugal  and  Spain  a  variety 
of  sundew  is  by  the  inhabitants  com- 
monly employed  in  place  of  fly-paper. 
Another  foreign  variety  lives  in  the  wa- 
ter, has  leaves  much  like  the  Venus'  fly- 
trap and  snaps  up  little  water  insects. 
These  plants  do  not  depend  for  food  en- 
tirely upon  the  insects  they  catch.  They 
are  all  provided  with  leaf-green  and  de- 
vour insects  only  in  an  incidental  way. 

The  eighteenth  order  includes  the 
riverweeds;  the  orpines;  a  family  of 
West  Australian  pitcher-plants ;  the  sax- 
ifrages, to  which  the  hydrangeas,  goose- 
berries and  a  number  of  herbs  belong; 
the  witch-hazels ;  the  sycamores ;  and  the 
roses.  In  the  last-named  family  are  in- 
cluded the  spiraeas,  apples,  quinces, 

mountain-ashes  and  June-berries,  the  roses,  strawberries  and  a 
number  of  related  herbs,  the  raspberries,  blackberries  and  bram- 
bles and  the  plums,  almonds,  peaches  and  apricots.  Further- 
more, in  this  eighteenth  order  is  included  the  great  pulse  family 
with  the  acacias,  the  sensitive  plants,  the  tamarinds,  the  red- 
buds,  the  sennas,  the  honey-locusts,  the  lupines,  brooms,  la- 
burnums, clovers,  indigo-plants,  locust-trees,  ground-peas,  pea- 
nuts, beans,  peas,  and  all  the  allied  varieties  in  which  the  type 
of  pod  known  as  the  legume  is  formed.  Besides,  there  are  some 
smaller  families  classified  here,  so  that  this  is  one  of  the  largest 
and  most  important  of  all  the  orders  of  flowering  plants. 


Minnesota  Plant  Life. 


281 


Riverweeds.  Of  the  rivenveed  family  there  is  a  single  Min- 
nesota species  which  grows  attached  to  stones  under  water  in 
strong  rapids  or  cataracts.  The  riverweed  belongs  to  a  family 
of  herbs  best  developed  in  the  tropics  and  very  remarkable  for 
marvelously  perfect  adaptation  to  the  submerged  life.  The 
plant-body  of  many  of  the  riverweeds  resembles  that  of  an 
alga,  the  leaves  being  poorly  distinguished  from  the  stem  on 
which  they  are  borne.  The  flowers  and  fruits  are  produced 
entirely  under  water  and  are  surrounded  by  involucres  resem- 
bling the  spathes  of  the  arum  family.  In  the  Minnesota  va- 
riety— the  only  one  common  in  North  America — the  flowers 

are  sessile,  there  is  no  perianth 
and  there  are  two  stamens  united 
together  at  the  base.  The  fruit- 
rudiment  is  ovoid,  with  two  short 
stigmas.  The  general  appearance 
of  the  plant  is  that  of  a  dense  tuft 
of  finely  divided  leaves  attached 
to  the  stones  at  the  bottom  of 
the  water.  The  flowers  are  small 
and  easily  recognized  by  the  two 
partly  fused  stamens,  standing 
like  a  little  fork  beside  the  ovary. 
In  the  fruit  arise  a  number  of 
small  seeds  with  straight  embryos 
and  without  albumen.  The 
riverweed  has  been  collected  in 
Brown.  Minnesota  on  the  International 

boundary,  in  the  Granite  lake  rapids,  at  Minnehaha  falls  and  at 
Lake  Pepin.  The  most  interesting  thing  about  the  riverweed 
is  its  entire  abandonment  of  terrestrial  methods  of  flower-pro- 
duction and  pollination.  While  pondweeds  are  compelled  to 
lift  their  spikes  of  flowers  above  the  surface  of  the  water  to 
accommodate  themselves  to  the  persistence  of  ancient  methods 
of  wind-distribution  in  vogue  during  the  days  when  their  an- 
cestors were  dwellers  on  the  land,  the  riverweeds  have  freed 
themselves  from  this  necessity  and  have  the  ability  to  main- 
tain themselves  quite  submerged  in  deep  water,  as  if  they  wei 
algae  Some  other  varieties  of  flowering  plants  flower  under 


FIG.   136.     River-weed.     After  Britton   and 


282 


Minnesota  Plant  Life. 


water,  as,  for  example,  the  marine  eel-grass,  so  common  along 
seashores  around  the  world.  This  plant  is  famous  for  its  de- 
velopment of  thread-shaped  pollen-spores — a  form  more  favor- 
able for  aquatic  pollination  than  the  ordinary  round  spores 
common  in  most  other  plants.  There  are  no  flowering  plants, 
however,  which  are  so  strongly  adapted  to  the  aquatic  life  as 
are  the  riverweeds.  Even  the  tiny  duckweeds,  floating  like 
green  specks  at  the  surface  of  quiet  pools  depend  upon  the  wind 
for  the  distribution  of  their  pollen  and  produce  their  pollen  sacs 
and  stigmas  in  the  air  as  did  their  terrestrial  progenitors. 

Stone-crops.  The  orpine  family  is  represented  in  Minnesota 
by  the  native  stone-crop 
and  the  introduced  uhen- 
and-c  hick  ens."  The 
stone-crop,  which  grows 
in  ditches  and  swamps,  is 
a  slender,  erect  plant  with 
smooth  leaves  and  stem. 
The  flowers  are  produced, 
at  the  tip  of  the  stem,  in 
cymes  on  recurving 
branches  from  one  to 
three  inches  in  length. 
The  flowers  have  five  se- 
pals, ten  stamens,  usually 
no  petals,  and  five  rather 
imperfectly  fused  carpels 
in  each  of  which  a  num- 
ber of  seed-rudiments  are  produced.  Many  of  the  orpine  fam- 
ily are  rock-dwelling  plants  and  belong  to  the  adaptational 
group  known  as  leaf-succulents.  The  "hen-and-chickens"  is  an 
example  of  this  group.  Its  leaves  are  very  fleshy  and  thick,  often 
grayish-green  in  color  and  arranged  in  rosettes,  from  the  centre 
of  which  the  erect,  central  flowering  stems  are  developed.  Such 
plants  inhabit  little  crevices  in  cliffs,  and  the  fleshy  character  of 
the  leaves  is  doubtless  in  response  to  the  difficulty  of  obtaining 
sufficient  moisture  for  the  roots.  The  ditch  stone-crop,  how- 
ever, prefers  moist  places,  and  has  leaves  of  quite  ordinary  ap- 
pearance. 


FIG.  137.     American  alum-root.     After  Britton  and 
Brown. 


Minnesota  Plant  Life. 


283 


Saxifrages.  The  saxifrage  family  includes  in  Minnesota  the 
gooseberries  and  currants,  of  which  there  are  nine  species ;  the 
saxifrages,  with  four  species,  one  of  which,  the  swamp  saxifrage, 
is  found  in  peat-bogs  and  tamarack  swamps  throughout  the 
state;  a  single  species  of  Sullivantia;  two  species  of  alum-root; 
two  miterworts ;  one  false  miterwort ;  and  one  golden  saxifrage. 
The  swamp  saxifrage  has  large,  rather  whitish  green,  long 
ovate  leaves  and  a  central  hollow  stem,  somewhat  thick  at  the 
base,  upon  which  cymes  of  flowers  are  arranged  in  an  open  pan- 
icle. Another  saxifrage  found  on  dry  rocks  along  the  north  shore 

of  Lake  Superior,  has 
rather  succulent  leaves, 
forming  a  thick  rosette  at 
the  base  of  the  flowering 
stem*  This  plant  propa- 
gates by  little  offsets  like 
the  hen-and-chickens. 

Alum-roots.  The  al- 
um-roots, common  on  dry 
hills  or  rocks,  have  leaves 
shaped  somewhat  like 
those  of  the  gooseberry 
and  erect  panicles  of  flow- 
ers at  the  end  of  a  slender 
axis.  The  flowers  are 
whitish-green  or  purplish 
and  inconspicuous.  There 
are  five  stamens.  The 
ovary  is  one  chambered, 
with  numerous  seed-rudiments  and  ripens  into  a  two-valved  pod 
which  splits  from  the  end,  curving  the  tips  away  from  each 
other.  The  two  varieties  in  Minnesota  are  distinguished  by 
the  appearance  of  the  flowers.  In  the  American  alum-root  the 
calyx  of  the  flower  is  bell-shaped  and  regular.  In  the  rough 
alum-root  the  calyx  is  bell-shaped  and  very  oblique  with  un- 
equal lobes.  Both  plants  are  sometimes  found  in  dry  woods 
but  are  more  abundant  as  rock  plants  on  high  ledges  or  as 
crevice  plants  on  barren  islands.  The  miterworts  and  golden 
saxifrages  are  delicate  little  herbs  with  leaves  shaped  some- 


FIG.  138.     Marsh  Parnafsia.    After  Britton  and  Brown. 


284  Minnesota  Plant  Life. 

what  like  those  of  the  gooseberry  and  with  the  general  saxifrage 
type  of  flower.  In  the  common  miterwort  or  bishop's  cap  the 
five  petals  are  shaped  like  tiny  feathers. 

Parnassias.  The  Parnassias,  of  which  one  species  is  com- 
mon throughout  the  state  while  the  other  two  grow  especially 
on  the  north  shore  of  Lake  Superior,  are  swamp  plants  with 
entire,  broadly  spoon-shaped,  strongly  ribbed  leaves  and  ter- 
minal solitary  flowers  of  a  white  or  creamy  yellow  color,  aris- 
ing at  the  end  of  a  slender  erect  axis.  Usually  a  single  sessile 
heart-shaped  leaf  is  displayed  one-third  of  the  way  up  the 
flowering  axis.  The  flowers  of  Parnassia  may  be  recognized 
by  the  little  clusters  of  imperfect  stamens  produced  at  the  base 
of  each  of  the  five  petals. 

Gooseberries  and  currants.  The  largest  genus  of  saxifrages 
in  Minnesota  is  the  one  to  which  the  gooseberries  and  cur- 
rants belong.  There  are  probably  six  gooseberries  in  the  state, 
and  the  different  sorts  are  recognized  by  the  shape  of  the  leaves 
and  the  character  of  the  fruit.  One,  the  prickly  gooseberry, 
is  common  everywhere,  and  in  this  species  the  fruits  are 
covered  with  prickles.  Of  smooth  gooseberries  there  are  four 
or  five  sorts  distinguished  by  characters  of  the  flowers  and 
leaves.  Of  currants  there  are  four  sorts,  among  which,  one,  the 
flowering-currant,  is  not  native.  The  other  three  are  the  skunk 
currant,  with  its  prostrate  branches  and  disagreeable  odor,  com- 
mon in  the  northern  part  of  the  state;  the  wild  black  currant, 
abundant  throughout  the  state;  and  the  red  currant,  most 
abundant  north  of  a  straight  line  connecting  Fergus  Falls  with 
Duluth.  The  gooseberries  have  the  flowers  arranged  for  the 
most  part  in  small  clusters  or  they  are  solitary,  while  the  cur- 
rants produce  racemes  of  flowers  ripening  into  bunches  of  fruit. 
The  fruits  are  spherical  berries,  having  a  somewhat  different 
taste  in  the  gooseberry  division  of  the  genus  from  that  char- 
acteristic of  the  currants.  Each  berry  contains  a  few  seeds 
with  slimy  or  gelatinous  outer  and  hard  inner  coats.  The 
flowering-currant,  with  its  bright  yellow  flowers,  is  a  native  of 
the  western  plains  and  is  abundantly  introduced  in  Minnesota. 

Witch-hazels.  The  witch-hazel  family  is  represented  in  Min- 
nesota by  a  single  species,  the  well-known  witch-hazel  of  the 
southern  part  of  the  state.  This  is  a  shrub  superficially  re- 


Minnesota  Plant  Life.  285 

sembling  the  hazel  in  some  respects,  but  with  bright  yellow 
flowers  in  the  axils  of  the  leaves.  The  flowers  are  remarkable 
for  blooming  during  the  autumn  of  the  year  as  the  leaves 
are  falling.  The  petals  are  very  slender  and  elongated,  and 
there  are  four  perfect  and  four  imperfect  stamens,  while  the 
capsule  opens  by  two  valves.  The  witch-hazel  is  much  used  in 
the  production  of  an  extract  reputed  to  have  healing  virtues 
similar  to  those  of  arnica,  but  by  some  believed  to  have  no 
medicinal  value  whatever. 

Sycamores.    Sycamore  trees  scarcely  occur  spontaneously  in 
Minnesota,  the  state  being  too  far  north  for  their  development. 


Chapter  XXX. 

Roses,  Peas  and  their  Relatives, 


The  rose  family  is  represented  in  Minnesota  by  from  sixty- 
five  to  seventy  species,  among  which  are  herbs,  shrubs  and  trees, 
while  all  unite  in  the  general  character  ot  the  flower. 

Meadow-sweets.  Here  are  to  be  grouped  the  Spiraeas, 
meadow-sweets  or  ninebarks,  of  which  there  are  three  varieties 
in  the  state.  The  most  common  is  the  willow-leafed  Spiraea 
a  frequent  and  abundant  meadow  plant  in  every  district.  All 
of  them  are  shrubs  with  alternate  leaves  —  in  the  ninebark  some- 
what lobed  and  shaped  a  little  like  the  leaves  of  the  currant,  but 
in  the  meadow-sweet  or  Spiraea,  with  the  outline  of  willow  leaves. 
The  flowers  are  borne  in  terminal  panicles,  or  large  clusters, 
and  in  two  of  the  species  are  of  a  white  or  slightly  purplish 
color,  while  in  the  third  they  are  of  a  handsome  pink.  The 
meadow-sweets  are  common  plants  in  swamps  and  swales  as 
well  as  in  meadows,  and  one  variety  is  very  abundant  on  the 
rocky  shores  of  northern  lakes,  growing  often  partly  submerged 
under  water.  While  much  smaller,  the  flowers  of  the  Spiraeas 
are  in  their  general  appearance  much  like  apple  blossoms. 

Crab-apples  and  chokeberries.  The  apples  and  mountain- 
ashes,  with  the  June-berries  and  hawthorns,  constitute  a  very 
clearly  defined  series  of  the  rose  family.  Of  apples  and  quinces, 
which  together  with  the  pears  form  a  characteristic  series,  there 
are  five  sorts  in  Minnesota  —  three  wild  crab-apples  and  two  va- 
rieties of  chokeberries.  There  is  no  difficulty  in  recognizing  these 
plants,  because  they  have  the  typical  apple  fruit.  The  common 
crab-apple  is  a  small  tree  with  ovate  to  triangular  leaves, 
distinguishable  from  the  western  crab-apple  or  chokeberry, 
which  also  occurs  in  the  state,  by  the  general  outline  of  the 
leaves.  In  the  western  crab-apple  the  leaves  are  oblong  or 
ovate,  but  not  so  triangular.  Still  another  form  of  crab-apple 
has  somewhat  larger  oval  leaves  with  shallow  notches  at  the 
margin. 


Minnesota  Plant  Life. 


287 


The  chokeberries  are  shrubs  ordinarily  to  be  looked  for  in 
swamps  or  damp  woods.  The  flowers  are  considerably  smaller 
than  those  of  the  crab-apples,  but  decidedly  similar.  The 
fruits,  too,  are  not  different  in  essential  particulars  from  those 
of  the  crab-apples,  but  are  not  so  large,  averaging  about  the 
size  of  a  well-grown  gooseberry.  In  one  of  the  chokeberries 
the  fruit  is  bright  red  when  ripe,  while  in  the  other  it  is  almost 
black. 

June-berries.    Of  June-berries  there  are  four  or  five  species 
growing  in  Minnesota.     These  are  all  shrubs  or  trees  with  flow- 
ers resembling  those  of    the  apple,  but  with  more  berry-like 
fruits,  smaller  on  the  whole  than  the  fruits  of  the  apples.     In 
the   common   June-berry 
the  fruit  is  spherical, 
sweet  to  the  taste  and  of 
a     reddish     color.      The 
shad-bush,  a    variety    of' 
June-berry,   may  be  dis- 
tinguished by  the  white, 
woolly  appearance  of  the 
foliage    when    young, 
changing  to  smooth  when 
older.     In  both  of  these 
varieties    the    leaves    are 
somewhat  elongated,  like 
plum   leaves.     In   the 
round-leaved  June-berry, 
the  leaves,  as  the  name 
indicates,  are  almost  round,  while  in  the  alder  June-berry  the 
leaves  are  oval,   notched  more  deeply  towards  the  tip  than 
towards  the  base. 

In  all  the  varieties  so  far  discussed  the  fruits  are  more 
less  apple-shaped.     One  other,  which  occurs  at  the  extreme 
northern  edge  of  the  state,  in  cold  bogs,  is  a  low  shrub,  smooth 
throughout,  with  a  purple  pear-shaped  fruit,  half  an  inch  or  s 

in  length. 

Hawthorns.     Neither  the  apples  nor  the  June-ben 
thorny,  and  by  this  character  they  may  be  distinguished  fron 


FIG.  139.     Hawthorn.    After  Britton  and  Brown. 


288 


Minnesota  Plant  Life. 


the  hawthorns,  which  have  somewhat  similar  fruits.  Haw- 
thorns are  commonly  furnished  with  slender,  pointed  branches, 
giving  to  the  twigs  a  peculiar  spurred  appearance.  Between 
the  different  varieties  it  is  exceedingly  difficult  to  discriminate. 
About  six  species  exist  within  the  state,  and  they  are  to  be  class- 
ified by  the  shapes  of  the  leaves  and  the  outlines  and  surfaces 
of  the  fruits.  The  flowers  are  borne  in  flat-topped  clusters, 
reminding  one  of  the  flat-topped  elder  inflorescences.  The 
fruits  are  never  large, 
being  in  all  the  species 
about  the  size  of  choke- 
berries.  Sometimes 
hawthorn  trees  fail  to 
produce  thorns  or  form 
them  but  sparingly.  It 
is  not  then  easy  to  dis- 
tinguish them  from  the 
June-berries  or  choke- 
berries;  but  in  such 
instances  the  flower 
clusters  are  usually  dis- 
tinctive, for  while  those 
of  the  hawthorn  are,  for 
the  most  part,  flat- 
topped,  the  lower  flow- 
ers having  longer  stems 
than  the  upper,  the  clus- 
ters in  June-berries  and 
chokeberries  are  pan- 
icled  or  but  slightly  flat- 
topped. 

Mountain-ashes.  The  mountain-ashes  are  very  close  to  the 
apples  and  hawthorns.  Indeed,  they  may  be  regarded  as 
apples  with  diminutive  fruits  and  compound  leaves.  Two 
sorts  of  mountain-ash  may  be  looked  for  in  the  Minnesota 
woods.  They  are  both  low  trees  with  compound,  feather- 
shaped  leaves  and  small  white  flowers  in  terminal,  compound, 
flat-topped  cymes.  The  fruits  are  little  red  berries,  quite  like 
the  apple  fruits,  except  that  the  core  has  not  the  papery  walls 


FIG.  140.     Apple-blossoms.     After  photograph  by 
Williams. 


Minnesota  Plant  Life. 


289 


of  the  apple.  They  may  be  distinguished  from  all  the  other 
apple-like  plants  by  their  compound  leaves.  The  American 
mountain-ash  is  discriminated  from  the  western  mountain-ash 
by  the  shape  of  the  leaflets.  In  the  first  named  species  they 
are  slender  and  willow-like,  while  in  the  other  they  are  elon- 
gated-oblong and  not  so  sharply  pointed.  The  fruits  in  the  two 
varieties  are  very  similar  but  average  larger  in  the  western 
mountain-ash.  Both  varieties  are  very  ornamental  as  lawn 
trees,  but  the  western  mountain-ash  is  more  desirable  for  culti- 
vation in  Minnesota  than  the  other,  on  account  of  the  larger 
and  handsomer  flat-topped 
clusters  of  fruits. 

Strawberries  and  fivefingers. 
A  group  of  herbs,  including 
the  strawberries,  fivefingers 
and  avens,  should  be  men- 
tioned here.  There  are  a  num- 
ber of  varieties  of  them,  some 
sorts  abundant  in  meadows 
and  fields,  others  distributed 
in  swamps  and  along  the 
shores  of  lakes.  The  straw- 
berries in  particular  are  abun- 
dant and  easily  recognized  by 
their  three-compounded  leaves, 
by  their  habit  of  producing 
runners  for  propagation  and 
by  their  clusters  of  little  seed- 
like  fruits  upon  the  swollen 

conical  axis  of  the  flower.  This  axis  becomes  red  and  fleshy  as 
it  matures,  and  is  the  edible  portion  of  the  strawberry.  The 
other  herbs,  such  as  the  fivefingers,  closely  resemble  the  straw- 
berries in  the  character  of  the  flower,  but  do  not  form  fleshy 
axes  for  their  fruits.  The  avens  is  an  erect  herb,  rather  easily 
mistaken  by  the  casual  observer  for  some  kind  of  anemone  in 
fruit.  One  sort  which  is  common  in  Minnesota  produces  fruit 
clusters  quite  similar  in  appearance  to  those  of  the  clematis, 
having  the  same  plumy  appendages  on  the  nutlets.  None  of 
these  herbs,  except  the  strawberry,  is  of  any  particular  economic 
importance.  They  are  all,  however,  throughout  the  state,  com- 


FIG.  141.     Marsh  fivefinger.    After  Britton 
and  Brown. 


290  Minnesota  Plant  Life. 

mon  objects  in  open  woods  and  along  the  edges  of  moist 
meadows.  The  way  to  distinguish  an  anemone  from  a  five- 
finger  or  avens  is  this :  the  flowers  of  the  fivefingers  have  appar- 
ently a  double  calyx  formed  by  the  uniting  in  pairs  of  the  stip- 
ules at  the  bases  of  the  calyx  leaves.  The  anemones  have  no 
such  double  calyx.  Besides,  the  stamens  in  the  anemones  and 
buttercups  are  arranged  in  spirals,  while  those  of  the  fivefingers 
and  avens  are  arranged  in  whorls. 

Agrimonies.  Two  curious  little  herbs,  known  as  agrimonies, 
have  leaves  resembling  rose  leaves,  the  flowers  in  narrow,  spike- 
like  racemes  and  the  calyx  swollen  up  around  the  fruit  and  fur- 
nished with  a  number  of  hooked  bristles.  The  little  fruits  which 
become  attached  to  one's  clothing  in  the  woods  in  autumn,  if 
they  are  conical  in  shape  and  if  the  base  of  the  cone  is  barbed, 
are  those  of  the  agrimony.  The  bristles  do  not  really  belong 
to  the  fruit,  but  arise  from  the  calyx,  illustrating  how  the  plant 
may  use  the  same  areas  for  different  purposes.  In  apples, 
mountain-ashes,  June-berries,  and  chokeberries  the  calyx  grew 
up  around  the  fruit  and  became  fleshy.  That  is  to  say,  the  real 
fruit  of  the  apple  is  the  core,  the  flesh  which  is  eaten  being  the 
outer  portion  of  the  flower  and  not  the  central  ovary  or  group 
of  ovaries.  The  agrimony  fruits,  like  those  of  the  apples,  pears, 
quinces  and  hawthorns,  are  adapted  to  animal  distribution ;  but 
the  method  of  distribution  is  different.  In  the  apples,  calyx- 
leaves  become  an  inducement  to  animals  to  eat  the  fruits  and 
thus  the  seeds,  remaining  uninjured,  are  distributed.  But  in 
agrimonies  the  calyx  is  so  constructed  that  with  its  inclosed 
fruit  and  seeds  it  attaches  itself  to  the  fur  of  animals  and  in  this 
manner  obtains  dissemination. 

Raspberries  and  blackberries.  Very  closely  related  to  the 
fivefingers  and  strawberries  are  the  brambles,  including  here 
the  varieties  with  edible  fruits  known  as  raspberries  and  black- 
berries. About  ten  species  occur  in  the  state.  The  different 
flavors  in  the  fruits  give  occasion  for  the  classification  into  rasp- 
berries and  blackberries,  and  there  are  no  important  structural 
differences,  since  both  plants  belong  to  the  same  genus.  They 
are  shrubs  or  herbs  with  characteristic  fruitlets  like  miniature 
plums  aggregated  together  upon  a  fleshy  swollen  axis  devel- 
oped from  the  centre  of  the  flower,  and  somewhat  like  the 
conical  base  of  the  strawberry  nutlets.  One  difference  between 


Minnesota  Plant  Life. 

291 

blackberries  and  raspberries  is  in  the  texture  of  this  axis  In 
raspberries  it  becomes  drier  and  the  cluster  of  fruitlcts  sepa- 
rates from  it,  but  in  blackberries  it  remains  fleshy  and  there 
3  no  separation  of  the  fruit  cluster  from  the  receptacle  Of 
raspberries  there  are  in  Minnesota  five  varieties,  including  the 
red  and  black  raspberries,  two  dwarfed  species,  and  the  sour 
raspberry,  in  which  the  fruit  is  less  pleasantly  flavored  than  in 
the  others.  Of  blackberries  there  are  four  sorts,— two  varieties 
of  high  blackberry,  one  low  blackberry  and  one  swamp  black- 
berry. 

In  all  these  plants  the  stems  are  shrubby.     In  the  Arctic 

dwarfed  raspberry  the  plant-body 
is  herbaceous,  unarmed,  and  only 
three  to  ten  inches  in  height,  but 
not  creeping.  Another  peculiar 
little  creeping  raspberry,  seldom 
found  in  Minnesota,  has  leaves 
like  those  of  the  violet,  and  might 
even  be  mistaken  for  a  violet  un- 
less seen  in  flower  or  fruit. 

Rose-bushes.  The  roses  are 
shrubs  with  large  and  conspicu- 
ous flowers  which  cannot  well  be 
mistaken  for  those  of  any  other 
variety.  The  different  sorts  in 
Minnesota  may  be  distinguished 
by  the  shape  of  the  leaflets,  the 
presence  or  absence  of  prickles, 
the  shape  of  the  fruit,  and  the 

stipules  on  the  leaves.  The  common  prairie  rose,  for  example, 
has  distinct  stipules  and  the  leaves  are  disposed  along  a  prickly 
stem.  There  are  usually  from  seven  to  nine  round-ovate  leaf- 
lets in  each  leaf.  The  smooth,  or  meadow  rose,  is  at  once 
known  from  the  prairie  rose  by  the  scarcity  of  prickles,  only  a 
few  of  which  ever  occur  upon  the  stem.  Neither  of  these 
varieties  climbs.  A  climbing  rose  is  found,  however,  in  thick- 
ets in  the  southeastern  portion  of  the  state.  In  this  there  are 
often  three  or  five  leaflets  to  the  leaf.  Yet  another  sort  is  rec- 
ognized by  the  prickly  midribs  of  the  leaves.  The  swamp  rose 
and  the  pasture  rose  may  be  known  by  the  presence  of  a  pair 


FIG.  142.     Roses.     After  photograph  by 
Williams. 


2Q2 


Minnesota  Plant  Life. 


of  extra  large  prickles  just  below  the  stipules  at  the  base  of 
each  leaf. 

This  description  does  not  extend  over  all  the  wild  roses  of 
the  state,  but  without  going  into  technical  details  gives  an  idea 
of  their  differences.  All  the  roses  are  marked  by  a  special 
type  of  fruit  which  may  be  compared,  perhaps,  to  a  strawberry 
turned  inside  out ;  that  is  to  say,  the  nutlets  or  fruits  are  aggre- 
gated not  upon  a  convex,  but  upon  a  concave  receptacle.  The 
calyx  grows  up  around  this  concave  end  of  the  flower,  and  the 


FIG.  143.    Sand-cherry  in  fruit.    After  Bailey.     Bull.  70,  Cornell  Ag.  Kxpt.  Station. 

nutlets  are  inclosed  within  its  red  and  fleshy  substance.  Some 
roses  have  the  fruits,  or  hips,  as  they  are  called,  protected  by 
a  growth  of  prickles,  while  in  others  they  are  smooth. 

Plums,  peaches  and  cherries.  A  well-marked  sub-family  of 
roses  includes  the  plums,  cherries,  peaches,  apricots  and  al- 
monds. These  are  all  trees  or  shrubs  with  bitter  bark  and 
foliage.  The  bark,  leaves,  and  seeds  contain  small  quantities 
'of  prussic  acid, — a  substance  which  has,  when  chemically  pre- 
pared, about  the  same  odor  as  the  kernel  of  a  peach  stone.  The 
flowers  are  of  the  ordinary  rose  type,  except  that  there  is  only 


Minnesota  Plant  Life. 


293 


a  single  carpel  instead  of  five  or  more  as  in  other  roses.  Thi> 
single  carpel,  or  pistil,  at  the  centre  of  the  flower,  contains  one 
or  two  seed-rudiments  and  the  fruit  matures  as  a  stone  fruit. 
The  outer  wall  of  the  pistil  becomes  fleshy,  while  the  inner  grows 
hard  and  produces  the  stone.  Inside,  the  one  or  two  seed- 
rudiments  mature  into  the  kernels.  Plums  have  a  smooth  or  waxy 
outer  surface  for  their  fruits,  while  peaches  and  apricots  have 
this  surface  downy.  In  almonds  the  fleshy  tract  does  not  de- 
velop and  the  nuts  may  be  described  as  peaches  with  dry  pulp. 
Of  plums  there  are  two  principal  varieties, 
—the  plums  proper  and  the  cherries.  In 
Minnesota  there  are  one  or  two  species 
of  plum,  including  the  very 
common  wild  plum,  a  tree 
ten  to  twenty  feet  in  height, 
with  red,  purplish  or  yellow 
fruits.  The  stone  is  flat- 
tened, with  one  edge  sharp 
and  the  other  grooved.  Be- 
sides this  common  variety, 
at  the  extreme  northern 
edge  of  the  state  are  trees 
of  the  Canada  plum,  aver- 
aging somewhat  larger  than 
the  ordinary  sort,  with 
broader  leaves  and  larger, 
longer  fruits.  In  addition 
to  these  two  varieties  of  true 
plums  there  are  six  sorts  of 
cherries.  Almost  the  only 
difference  between  the  plums  and  the  cherries  is  the  flavor  of 
the  fruit,  though  cherries  as  a  class  have  rather  more  globular 
fruits  than  plums.  The  Minnesota  varieties  are  the  dwarfed 
or  sand-cherry,  common  on  sandy  beaches,  especially  in  the 
northern  part  of  the  state ;  the  wedge-leafed  cherry  with  fruits 
four  or  five  lines  broad;  the  western  sand-cherry,  resembling 
the  wedge-leafed  cherry  in  its  foliage  but  with  fruits  nearly 
twice  as  large,  found  on  prairies  in  the  western  part  of  the  state ; 
the  pin-cherries  with  sour  small  fruits,  without  bloom,  with 


144.  A  cluster  of  choke-cherry 
flowers  and  a  single  flower  dis- 
sected. After  Atkinson. 


294  Minnesota  Plant  Life. 

spherical  stones  and  arranged  in  clusters  of  three  or  four;  the 
choke-cherry,  with  fruits  of  a  red  color  or  sometimes  nearly 
black,  in  clusters  like  those  of  the  currant ;  and  the  black  cher- 
ries, forming  their  fruits  in  clusters  similar  to  the  last  men- 
tioned, but  always  dark  purple  or  black  in  color  and  somewhat 
flattened  vertically.  The  choke-cherry  can  be  distinguished 
from  the  black  cherry  by  the  very  astringent  taste  it  possesses. 
The  fruit  of  the  black  cherry  is  sweet  and  not  so  astringent. 

Comparison  of  different  types  of  rose  fruit.  The  fruits  in 
the  various  sorts  of  roses  appear  to  be  quite  dissimilar,  while 
in  reality  they  are  but  different  elaborations  of  the  same  gen- 
eral types.  It  may  serve  to  explain  them  if  they  are  briefly 
compared  with  each  other  and  described  as  modifications  of 
some  common  fundamental  form.  In  the  first  place  it  should 
be  noticed  that  the  number  of  carpels  in  the  flower  varies 
from  one  in  the  plums  and  peaches  to  fifty  and  more  in  the 
strawberries.  These  carpels  are  generally  separate  from  each 
other,  forming  independent  pistils;  but  in  the  spiraeas,  apples, 
mountain-ashes  and  their  relatives,  the  small  number  of  carpels, 
ordinarily  four  or  five,  are  produced  close  together,  so  that  they 
seem  almost  to  blend  in  one  body.  In  other  instances  the 
carpels  are  quite  distinct  and  separate,  as  in  the  strawberry. 
An  apple  may  be  compared  to  five  almond  nuts  placed  close 
together  and  surrounded  by  a  thick  fleshy  layer.  Each  seg- 
ment of  the  apple  core  is  a  ripened  carpel  containing  one  or 
two  seeds.  A  strawberry  may  be  compared  to  an  apple  core 
with  the  flesh  removed  and  the  number  of  carpels  increased  to 
fifty  or  more,  very  much  diminished  in  size  and  situated  on  the 
surface  of  a  swollen  fleshy  axis.  A  plum,  or  cherry,  or  peach, 
may  be  compared  to  one  segment  of  an  apple  core  with  the 
papery  membrane  greatly  thickened  and  converted  into  two 
layers,  the  outer  soft  and  pulpy,  the  inner  hard  and  stony.  A 
blackberry  may  be  compared  to  a  strawberry  in  which  all  the 
nutlets  have  matured  after  the  fashion  of  plums  or  cherries. 
A  raspberry  may  be  compared  to  a  strawberry  with  a  dry  pulpy 
centre  and  plum-like  nutlets  which  separate  from  their  axis  in 
a  group.  The  curious  bur-like  fruit  of  the  agrimony  may  be 
compared  to  an  apple  of  conical  shape  with  the  fleshy  part 
modified  into  a  layer  on  which  are  arranged  numerous  prickles 


Minnesota  Plant  Life.  295 

with  hooked  ends.  The  clematis-like  fruit  of  the  avens  may 
be  compared  to  a  strawberry  in  which  the  pulpy  part  is  dry 
and  the  ends  of  the  nutlets  are  prolonged  into  plumes,  enabling 
each  nutlet  to  be  distributed  by  the  wind. 

The  majority  of  the  rose  fruits  are  adapted  to  animal  distri- 
bution, but  the  fivefingers  and  the  avens  depend  rather  upon 
the  agency  of  the  wind.  The  rose  hip,  as  has  been  said,  may 
be  compared  to  a  strawberry  turned  inside  out,  with  an  apple- 
like  pulp  growing  up  around  it.  One  can  easily  see  at  the  end 
of  an  apple  opposite  the  stem,  and  at  the  end  of  the  rose  hip 
more  clearly  still,  the  five  points  of  the  five  calyx  leaves,  which 
have  become  fleshy  and  assist  in  the  distribution  of  the  seeds. 
The  colors,  perfumes,  essences  and  sugars  of  the  ripe  fruiting 
areas,  whether  these  areas  be  the  axis  of  the  flower,  as  in  the 
strawberry,  the  swollen  calyx  leaves,  as  in  the  apples,  haw- 
thorns, pears  and  rose  hips,  or  the  ovary  walls,  as  in  the  plums 
and  cherries,  are  in  all  instances  adaptations  for  the  attraction 
of  birds  and  animals.  So  that,  in  being  eaten,  such  fruits 
accomplish  their  own  ends  and  are  not  to  be  regarded  as  un- 
fortunate, like  the  fruits  of  wheat  and  corn  that  never  "intended" 
themselves  to  be  eaten,  but  stored  up  their  food  materials  en- 
tirely for  the  benefit  of  their  own  enfolded  plantlets.  From 
this  point  of  view  it  is  apparent  that  there  are  two  classes  of 
edible  fruits,  those  made  edible  by  the  plant  for  animal  distri- 
bution, and  those  adapted  to  the  nourishment  of  the  seedlings, 
but  seized  by  animals  contrary  to  the  well-being  of  the  plant. 
Of  the  former  class  apples  are  examples,  of  the  latter,  the  cereal 
grains. 

The  pea  family.  Related  to  the  roses  is  the  great  pulse 
family  in  which  the  pod-bearing  plants  of  the  world  are  classi- 
fied. '  The  lower  genera  of  pulses  have  more  or  less  regular 
flowers  with  radial  symmetry,  but  the  higher  genera  form  but- 
terfly-shaped flowers  like  those  of  the  sweet  peas,  and  of  a  shape 
distinct  from  that  of  any  other  flowers  in  the  plant  kingdom. 
There  is  never  any  doubt  whatever  about  the  classification  of 
a  plant  if  it  shows  the  butterfly-shaped  blossom.  The  pulse 
family  as  a  whole,  however,  is  a  group  based  rather  upon  fruit 
than  upon  flower  structure,  for  all  the  species  are  marked  by 
the  production  of  pods  or  legumes.  The  legume  is  a  fruit 


296 


Minnesota  Plant  Life. 


developed  from  a  single  carpel,  with  from  one  to  many  seed- 
rudiments  produced  in  a  row  along  one  side,  in  the  interior. 
The  forms  of  pods  are  very  various.  Sometimes  they  are  shaped 
quite  like  the  familiar  pea-pods  or  bean-pods.  Again  they  are 
broken  up  into  joints,  each  joint  containing  a  single  seed.  Often 
the  pods  are  coiled  like  snail  shells.  Some  varieties  have  small 
pods,  reminding  one,  in  their  appearance,  of  the  nutlets  of  the 
strawberry,  but  differing  in  their  almost  universal  habit  of 
opening  down  both  edges  to  release  the  seed.  About  7,000 
species  are  included  in  the 
pulse  family,  making  it  al- 
most three  times  as  large  as 
the  rose  family.  The  lower 
division  of  pulses,  in  which 
the  flowers  are  not  of  the 
true  butterfly  shape,  though 
sometimes  approaching  it,  is 
represented  in  Minnesota  by 
two  trees — the  redbud  and 
the  Kentucky  coffee-tree— 
and  four  herbs,  including 
three  sennas  and  a  desman- 
thus. 

Redbud  trees.  The  red- 
bud,  or  Judas-tree,  is  re- 
ported as  occurring  in  the 
extreme  southern  portion  of 

the  State,  but  the  Only  Speci-   FlG- 145-     Kentucky  coffee-tree.     After  Britten  and 
. ,  T      ,  Brown. 

mens  that    I    know  of   are 

cultivated,  and  it  is  probably  not  native  to  Minnesota.  The 
flowers  have  the  look  of  the  butterfly  flowers  of  the  higher 
genera,  but  the  broad  petal,  known  as  the  standard,  is  inclosed 
by  the  wings  in  the  bud.  In  the  true  butterfly  flowers  the 
reverse  condition  obtains.  The  leaves  of  the  redbud  are  heart- 
shaped  and  the  flowers  are  pink  and  borne  in  short  lateral  clus- 
ters. The  fruit  matures  into  a  flat,  oblong  pod  which  opens 
like  the  pod  of  a  locust.  The  wood  is  heavy,  coarse-grained, 
dark  brown  or  red,  with  lighter  colored  sap-wood. 


Minnesota  Plant  Life.  207 

Kentucky  coffee-trees.  The  Kentucky  coffee-tree  is  a  large 
forest  tree  indigenous,  but  somewhat  infrequent,  in  the  southern 
part  of  the  state.  It  is  especially  abundant  near  Mankato,  in 
Nicollet  county.  The  leaves  are  doubly  pinnate  and  the  flow- 
ers are  produced  in  racemes  and  are  regular  in  appearance. 
Some  of  them  are  staminate,  others  pistillate,  while  still  others 
are  provided  with  both  stamens  and  pistils.  The  pod  when 
fully  grown  is  from  five  to  ten  inches  long  and  two  inches  wide, 
somewhat  flattened,  of  a  dark  brown  color,  with  several  seeds. 
These  pods  hang  unopened  on  the  branches  throughout  the 
winter.  In  the  following  spring  they  split  along  the  edges  and 
reveal  the  large  brown  beans,  which  are  remarkable  for  their 
exceedingly  hard  coats,  their  albumen  and  the  orange-colored 
seed-leaves  of  the  embryo.  The  wood  of  the  tree  is  light  brown 
tinted  with  red  and  of  some  value  in  cabinet-making.  The 
coffee-trees  select  rich  deep  woods  as  their  habitat,  and  are 
beautiful  forms  under  cultivation.  They  cannot  be  mistaken 
for  any  other  of  the  native  Minnesota  varieties,  since  their  large, 
thick  pods  are  altogether  distinctive. 

Sennas.  The  sennas  are  also  known  as  sensitive  pe.as  or 
wild  sensitive-plants.  The  three  varieties  which  grow  in  Min- 
nesota produce  yellow  flowers,  almost  regular, — that  is,  rose- 
like  and  not  two-sided  in  appearance.  The  American  senna 
has  curved,  rather  smooth  pods,  three  to  four  inches  in  length. 
The  large-flowered  sensitive  pea  has  for  the  most  part  straight 
and  slightly  hairy  pods,  while  the  small-flowered  has  shorter 
straight  pods  and  flowers  considerably  less  than  half  the  size 
of  the  other.  The  desmanthus  is  one  of  the  pod-bearing  plants 
in  which  the  pods  are  clustered  together  in  heads.  It  is  a 
small  herb  with  doubly  pinnate,  fern-like  leaves,  regular  flowers 
aggregated  in  spherical  heads,  and  short  curved  pods  clustered 
together  in  dense  heads,  each  pod  containing  from  two  to  five 
seeds.  These  plants  would  not  be  mistaken  for  clovers,  in 
which  the  pods  are  also  clustered,  on  account  of  their  fern-like 
leaves  and  regular  flowers.  Besides,  the  pods  are  very  much 
larger. 

Of  the  pulses,  with  butterfly-shaped  flowers,  there  arc  be- 
tween 75  and  80  species  in  the  state,  including  the  false  indigos, 
the  wild  peanuts  and  wild  beans,  the  vetches,  prairie  clovers 


298 


Minnesota  Plant  Life. 


and  tick-trefoils,  the  wild  licorices,  the  ground-plums,  locust 
trees,  pommes  de  terre,  sweet  clovers,  lucernes,  alfalfas,  red, 
white  and  yellow  clovers,  lupines  and  rattle-boxes.  Most  of 
these  are  herbs.  A  few,  like  the  false  indigos  or  lead-plants, 
are  shrubs,  and  one,  the  locust,  is  a  well-known  tree. 

Herbaceous  false  indigos  and  rattle-boxes.  There  are  two 
different  kinds  of  plants  belonging  to  different  genera,  known 
under  the  general  name  of  false  indigo.  Some  of  them  are  herbs 
with  creamy  or  white  flowers  in  conspicuous  racemes.  Three 
kinds  of  herbaceous  false  indigos  are  known  to  occur  in  Min- 
nesota. The  pods  in  these 
plants  are  inflated  and  ovoid 
in  shape.  The  flowers  of  the 
white  false  indigo  turn  black 
in  drying.  The  leaves  consist 
for  the  most  part  of  three  leaf- 
lets and  the  plants  are  large, 
averaging  from  two  to  four 
feet  in  height.  Related  to 
these  false  indigos  are  the  rat- 
tle-boxes. The  Minnesota 
species  has  apparently  simple 
leaves  with  prominent  stipules 
at  the  base  of  some.  The 
pods  are  ovoid  and  inflated 
and  the  seeds  rattle  in  them, 
giving  the  occasion  for  the 
common  name. 

Lupines,  sweet  clovers  and  clovers.  Lupines,  of  which 
one  species  is  common  in  Minnesota,  have  the  flowers  arranged 
in  terminal,  conspicuous  racemes  like  the  herbaceous  false 
indigo  flowers.  The  leaflets,  however,  are  seven  to  eleven  in 
number,  growing  out  in  radial  fashion  from  the  tip  of  their 
common  stem.  The  flowers  are  generally  blue  and  the  whole 
plant  is  of  an  erect  habit,  from  one  to  two  feet  in  height.  The 
pods  are  not  much  inflated,  but  flattened  and  leathery.  By 
means  of  the  leaves  there  is  no  difficulty  in  distinguishing  these 
plants  from  other  pulses.  The  lucerne,  or  alfalfa,  has  violet 
or  purple  flowers  aggregated  in  loose  clover-like  heads  or 
racemes.  The  pod  in  this  variety  is  twisted  up  like  a  snail  shell. 


FIG.  146.     Wild  lupine.     After  Britton  and 
Brown. 


Minnesota  Plant  Life.  299 

The  sweet  clovers  are  represented  in  Minnesota  by  two 
varieties,  the  white  sweet  clover  and  the  yellow.  These  are 
bushy,  branching  herbs  sometimes  eight  or  nine  feet  in  height. 
The  small  flowers  are  arranged  in  slender  racemes.  The  pods 
are  short-ovoid,  and  often — unlike  most  legumes — fail  to  open. 
The  peculiar  fragrance  of  the  flowers  indicates  adaptation  to 
insect  pollination. 

Six  or  seven  kinds  of  clover,  only  one  of  which  is  native, 
occur  throughout  the  state.  These  are  plants  with  leaves  com- 
posed of  three  leaflets,  and  flowers  aggregated  on  short  pedicels 
in  more  or  less  globular  or  elongated  heads.  The  flowers  at 


FIG.  147.     Sweet-clover  bushes.     After  photograph  by  Williams. 

the  edge  of  the  head  mature  first,  and,  as  they  are  pollinated, 
often  curve  downwards,  leaving  the  field  clear  to  the  unpol- 
linated  flowers  to  attract  insects.  The  pods  of  the  clovers,  like 
those  of  the  sweet  clovers,  often  fail  to  open,  and,  when  they  do, 
separate  along  only  one  of  the  margins.  If  it  were  not  for  the 
butterfly-shaped  flowers  such  plants  might  escape  classification 
as  pulses.  The  three  most  common  clovers  in  the  state  are  the 
prostrate,  with  branches  lying  upon  the  ground,  the  common 
white,  and  the  red  clover.  The  flowers  of  the  prostrate  clover 
are  yellow.  Besides  these,  there  are  a  few  other  introduced 
clovers,  one  of  which  may  be  known  by  its  oblong  heads 


3°° 


Minnesota  Plant  Life. 


Rather  closely  connected  with  the  clovers  are  the  little  herbs 
known  as  lotuses — no  relatives,  however,  of  the  water-lily 
lotuses,  for  this  is  an  instance  where  common  names  are  con- 
fusing. In  these  plants  the  pods  are  more  elongated.  They 
occur  singly  and  hang  down  in  a  limp  position  when  mature, 
while  the  flowers  are  small,  rose  colored  and  with  darker  stand- 
ard. The  leaves  are  for  the  most  part  made  up  of  three  leaflets. 
A  lotus  may  be  known  by  its  solitary  drooping  pods. 

Indian  turnips.  The  pomme  de  terre,  or  prairie-turnip,  or 
Indian  turnip,  is  an  herb  somewhat  branched,  of  robust  habit, 
and  arising  from  a  tuberous  root.  The  flowers  are  in  hairy 
ovoid  spikes  and  the  leaves  are 
made  up  of  five  radiating  leaf- 
lets. The  pod  is  oblong, 
smooth  and  inclosed  in  the 
calyx.  Two  other  plants  of 
this  genus  are  abundant  in  the 
state.  One  is  conspicuous  for 
its  silvery  leaves  and  is  known 
as  the  silver-leafed  prairie- 
clover.  The  silvery  appear- 
ance, as  in  the  buffalo-berries, 
is  given  by  hairs  on  the  sur- 
face of  the  leaves.  There  are 
from  three  to  five  leaflets  to 
each  leaf  and  the  flowers  are 
of  a  blue  color,  sessile  and  in  small  clusters.  Another  variety, 
the  many-flowered  prairie-clover,  has  leaves  similar  in  form  to 
the  silver-leafed  variety,  but  without  the  hairs  which  give  them 
the  metallic  lustre.  In  this  variety  there  are  a  number  of  small 
blue  flowers  aggregated  in  loose  racemes. 

Shrubby  false  indigos.  The  shrubby  false  indigos  occur  in 
Minnesota  in  three  varieties.  These  plants  are  remarkable  for 
the  modification  of  the  butterfly-shaped  flower,  for  all  of  the 
five  petals,  except  the  standard,  have  disappeared,  so  that  the 
flower  has  but  one  petal.  This  is  of  a  purplish,  violet  or  blue 
color.  The  leaves  are  pinnate  with  from  twenty  to  fifty  leaflets, 
arranged  opposite  each  other  on  their  common  midrib.  The 
large  false  indigo  is  from  five  to  twenty  feet  in  height,  with 


FIG.  148.    White  clover.    After  photograph 
bv  Williams. 


Minnesota  Plant  Life.  -»oi 

spike-like  purple  racemes  of  flowers  from  three  to  six  inches 
in  length.  The  pods  are  short,  usually  with  two  seeds,  and  the 
surfaces  are  covered  with  little  oil  glands.  It  is  common  along 
the  shores  of  lakes.  The  low  false  indigo  is  a  smooth  shrub, 
not  over  a  foot  in  height.  The  flowers  are  arranged  in  spicate 
racemes,  usually  solitary.  They  are  of  a  purple  color  and  sweet- 
scented.  The  plant  is  at  home  in  the  southwestern  districts, 
preferring  the  prairie  to  the  forest. 

The  lead-plant,  which  is  one  of  the  most  abundant  prairie 
shrubs  in  the  Minnesota  valley,  is  covered  with  white  hairs  and 
averages  from  one  to  three  feet  in  height.  The  leaves  develop 
twice  as  many  leaflets  as  in  the  other  varieties,  sometimes  twenty 
or  more  on  each  side  of  the  common  midrib.  Several  blue 
racemes  of  flowers  generally  occur  close  together.  The  pods 
are  hairy  and  not  markedly  glandular. 

Prairie-clovers.  Of  the  true  prairie-clovers  there  are  three 
Minnesota  species, — the  purple,  the  white,  and  the  silky.  These 
plants  have  leaves  made  up,  in  the  silky  variety,  of  from  ten  to 
twenty  leaflets,  and  in  the  other  two,  of  from  five  to  nine.  The 
purple  prairie-clover  has  commonly  from  three  to  five  leaflets 
and  in  all  the  varieties  they  are  small  and  slender.  The  flowers 
are  arranged  in  dense  spikes,  and  very  often  such  spikes  will 
be  found  with  girdles  of  flowers  blooming  around  their  middles, 
while  above  the  buds  are  still  unopened  and  below  the  fruits 
have  set  and  the  petals  withered.  By  this  habit,  together  with 
their  other  characters,  they  may  be  recognized. 

Locust-trees.  The  locust,  or  false  acacia,  is  a  handsome  tree 
and  is  noted  for  its  beautiful  pendulous  racemes  of  large  white 
flowers,  very  fragrant  and  opening  in  the  late  spring.  The 
trunk,  farther  south,  is  sometimes  three  or  four  feet  in  diameter, 
but  rarely  exceeds  a  foot  in  the  colder  climate  of  Minnesota. 
The  leaves  are  made  up  of  from  eleven  to  fifteen  leaflets  pin- 
nately  arranged.  The  pods  are  much  flattened,  with  winged 
edges,  and  the  seeds  ripen  in  separate  chambers,  and,  when  the 
pod  opens,  remain  adherent,  some  of  them  to  one  side  of  the 
pod  and  others  to  the  other.  The  halves  of  the  thin  pod  serve 
the  seeds  as  wings  for  their  distribution  by  the  wind.  Young 
twigs  of  the  locust  tree  have  thorns  at  the  bases  of  the  leaves, 
but  the  older  branches  are  unarmed. 


302  Minnesota  Plant  Life. 

Ground-plums.  The  common  ground-plum  of  the  prairies 
is  one  member  of  a  little  group  of  pulses  including  about  ten 
species  in  Minnesota.  Most  of  them  have  slender,  purplish, 
lilac  or  whitish  flowers  in  rather  loose  racemes.  The  leaflets 
are  much  like  those  of  the  smaller  shrubby  false  indigos ;  that 
is,  they  are  composed  of  numerous  small  oval  leaflets  on  each 
side  of  a  slender  axis.  In  the  ground-plum  the  pod,  when  it 
matures,  is  fleshy  and  may  be  eaten  when  cooked.  Not  all  of 
the  Minnesota  varieties  of  ground-plum  have  this  fleshy  pod. 
In  others  the  pod  is  quite  dry. 

Two  plants  closely  related  to  the  ground-plum  may  be  dis- 
tinguished from  it  by  the  longer,  more  conspicuous  racemes 
of  showy  flowers.  One  of  them  in  particular,  which  grows  in 
the  western  part  of  the  state,  has  bluish-purple  flowers  on  a  tall, 
central,  erect  stalk  and  is  a  very  prominent  flower  of  the  prairie. 
This  plant  is  sometimes  called  loco-weed  or  loco-vetch.  The 
other  member  of  its  genus  is  of  a  beautiful  silvery  lustre,  owing 
to  the  soft  white  hairs  that  cover  the  leaflets  and  their  axes. 
In  neither  of  these  loco-weeds  is  there  a  branching  plant-body 
above  ground,  but  the  leaves  seem  to  spring  in  a  tuft  from  the 
roots,  while  in  the  centre  the  erect  flowering  axis  lifts  itself 
above  their  tips.  The  pods  are  incompletely  divided  into  two 
chambers  by  a  deep  partition  extending  lengthwise  through  the 
pod  almost  to  the  back. 

Wild  licorice.  A  common  herb  of  the  Minnesota  prairie  is 
the  wild  licorice.  This  plant  may  always  be  recognized  when 
in  fruit  by  the  ovoid  pods  covered  with  hooked  bristles.  No 
other  Minnesota  pulse  has  just  this  sort  of  pod,  which  is,  indeed, 
not  unlike  a  small  cockle-bur  head.  The  flowers,  produced  in 
rather  dense  spikes,  are  of  a  cream  color  varying  to  white.  In 
these  plants  the  roots  are  thick  and  sweet  to  the  taste  and  are 
sometimes  used  as  a  substitute  for  licorice.  The  flavor,  how- 
ever, is  different  from  that  of  the  true  licorice  and  is  scarcely 
so  agreeable.  The  leaves  are  of  the  same  general  character  as 
those  of  the  last  plant  mentioned,  except  that  they  are  not  sil- 
very in  color,  and  are  marked  by  minute  glandular  dots. 

Tick-trefoils.  The  tick-trefoils  are  characterized  by  their 
pods  which  are  constricted  between  the  seeds  and  separate  into 


Minnesota  Plant  Life. 


303 


pieces,  each  pod  appearing  to  be  made  up  of  joints.  One  kind. 
rare  in  Minnesota,  and  limited  to  the  north  shore  of  Lake 
Superior,  has  the  flowers  in  rather  dense,  violet-colored,  ter- 
minal racemes.  The  pod  consists  of  from  three  to  five  smooth 
joints  shaped  somewhat  like  eggs.  The  other  tick-trefoils,  of 
which  there  are  eight  or  nine  reported  to  grow  within  the  con- 
fines of  the  state,  have  much  less  noticeable  flower  clusters,  and 
the  flowers  are  small  and  loosely  arranged  on  their  axes.  Some- 
times they  are  terminal  and  sometimes  produced  in  the  angle 

above  the  leaves.  The  pod  is 
very  flat  and  usually  separat- 
ed into  a  number  of  joints. 
Sometimes  the  pod  is 
straight  along  one  edge, 
while  the  other  edge  is  in- 
dented like  the  teeth  of  a  saw ; 
but  in  other  instances  both 
sides  of  the  pod  are  indent- 
ed. The  different  kinds  of 
tick-trefoils  cannot  be  dis- 
tinguished from  each  other 
without  a  critical  examina- 
tion ;  but  it  may  be  said  that 
their  principal  differences 
are  in  the  shapes  of  the  leaf- 
lets, the  arrangements  of  the 

FIG.  149.    Tick-trefoil.    After  Britton  and  Brown,      pods  in  clusters,  the  SlirfaCCS 

of  the  pods  and  their  methods  of  jointing.  They  are  found  for 
the  most  part  in  woodlands  and  usually  stand  up  from  two  to 
six  feet  in  height.  In  most  of  them  the  pods  are  provided  with 
hooked  bristles,  by  means  of  which  they  cling,  either  as  a  whole, 
or  broken  up  into  their  joints,  upon  the  fur  of  passing  animals, 
or  upon  the  clothing  of  their  human  visitors. 

Bush  clovers.  Seven  species  of  bush  clovers  are  reported 
from  Minnesota.  Several  of  these  are  known  as  wand  plants ; 
that  is,  plants  which  stand  up  slim  and  tall  without  any  lateral 
branches.  One  of  them,  the  bushy  headed  or  round  headed 
bush  clover,  is  a  common  object  with  its  brown,  pod-bearing 


304  Minnesota  Plant  Life. 

heads  aggregated  in  coffee-colored  clusters  at  the  top  of  a 
slender  stem  from  two  to  five  feet  high.  The  stems  bear  a 
number  of  three-compounded  leaves  in  which  the  leaflets  are 
shaped  somewhat  like  those  of  the  willow.  One  of  these  bush 
clovers  has  a  creeping  stem  and  might  be  taken  for  a  true  clover 
were  it  not  for  the  egg-shaped  pods  which  are  larger  and  dis- 
similar to  those  of  the  true  clovers. 

Vetches  and  beach  peas.  The  vetches  and  beach  peas  may 
be  recognized,  wherever  they  occur,  by  the  formation  of  tendrils 
at  the  tips  of  their  leaves.  There  are  about  ten  species  in 
Minnesota.  They  are  found  in  woods  and  swales  and  one 
variety  is  very  conspicuous  on  sandy  and  gravelly  beaches 
throughout  the  northern  part  of  the  state,  being  particularly 
abundant  at  Lake  of  the  Woods  and  Red  lake.  This  variety, 
which  is  known  as  the  beach  pea,  is  seen  at  its  best  on  the  sea- 
shore. The  differences  in  the  vetches  lie  in  the  shapes  of  the 
leaves  and  pods,  the  colors  and  sizes  of  the  flowers  and  the 
development  of  the  tendrils.  In  general,  however,  they  are 
supplied  with  pinnately  compounded  leaves  with  one  or  two 
tendrils  taking  the  place  of  the  terminal  leaflet  or  pair  of  leaflets. 

Wild  peanuts  and  wild  beans.  Not  far  removed  from  the 
beach  peas  are  the  groundnuts,  wild  peanuts  and  wild  beans. 
In  these  there  are  commonly  from  three  to  five  broad  leaflets 
to  each  leaf.  The  stems  are  slender  and  twine  or  climb  over 
the  vegetation  near  them.  The  flowers  are  small,  blue,  pink 
or  violet,  and  are  generally  gathered  together  in  rather  small 
clusters.  These  plants  are  abundant  in  the  edges  of  woods. 
The  wild  peanut  forms  two  kinds  of  flowers,  small  purple  or 
white,  ordinary  butterfly-shaped  flowers  on  lateral  racemes,  and 
peculiar  little  flowers  without  petals,  on  certain  slender  pros- 
trate stems  which  trail  along  the  ground.  By  means  of  these 
two  kinds  of  flowers  there  is  no  difficulty  in  recognizing  the 
wild  peanut.  The  wild  beans  resemble  the  wild  peanut  in  their 
general  appearance,  but  are  devoid  of  the  curious  inconspicuous 
flowers.  The  groundnut  usually  displays  five  leaflets  in  each 
leaf  instead  of  three,  but  has  the  same  slender  vine-like  habit 
of  growth  that  characterizes  the  others.  All  these  plants  will 
be  found  in  thickets  and  underbrush,  trailing  or  climbing  over 
the  bushes  and  thus  exposing  their  own  foliage  to  the  light. 


Chapter  XXXI. 

From  Geraniums  to  Maples  and  Touch-me-nots. 

if 

The  nineteenth  order  includes  the  geraniums,  the  wood- 
sorrels,  the  nasturtium  vines,  the  flaxes,  the  rues  and  prickly 
ashes,  the  polygalas,  the  spurges,  castor-beans,  and  tapiocas,  the 
water-starworts  and  several  families  not  represented  in  North 
America.  A  variety  of  interesting  plants  in  this  order  are 
cultivated,  or  are  employed  for  various  economic  purposes. 
For  example,  the  coca  tree,  from  which  the  well-known  anes- 
thetic, cocaine,  is  manufactured,  should  be  grouped  here;  also 
the  oranges,  limes  and  lemons,  and  the  ailanthus  tree,  introduced 
from  China.  To  the  spurge  family,  too,  of  this  order,  there 
belong  a  number  of  singular  cactus-like  plants  most  abundant 
in  South  Africa.  Several  of  the  families  are  represented  in 
Minnesota,  but  most  of  them  by  only  a  few  species. 

Geraniums.  Four  varieties  of  geranium  occur  wild  in  Min- 
nesota. These  all  have  regular  flax-like  flowers  and  slender 
capsules  which  open  by  five  clefts  running  lengthwise  of  the 
pod.  A  peculiarity  of  the  geranium  pod  is  that,  when  it  opens, 
it  does  so  suddenly,  splitting  from  the  base  upward.  Five 
pieces,  each  carrying  a  seed  at  its  lower  end,  split  off  in  this 
manner  from  a  central  column  and  the  seeds  are  projected  some 
distance  into  the  air  as  if  thrown  from  a  catapult.  The  differ- 
ent kinds  of  wild  geraniums  may  be  distinguished  by  their 
leaves.  The  common  spotted-leafed  geranium  has  rose-colored 
flowers  and  leaves  palmately  divided  and  spotted.  The  red- 
robin  has  much  smaller  leaves  without  the  conspicuous  spots. 
The  Carolina  geranium  has  its  leaves  cut  up  into  finer  seg- 
ments than  the  others  and  the  flowers  are  of  a  pale,  whitish  hue. 

Wood-sorrels.  The  wood-sorrels  are  well-known  for  their 
three-leafleted  leaves,  not  unlike  those  of  the  white  clover,  but 
with  a  distinct  acid  taste.  There  are  at  least  three  varieties 

21 


306  Minnesota  Plant  Life. 

in  Minnesota  and  probably  a  fourth.  In  one,  the  white  wood- 
sorrel,  found  only  in  the  northern  part  of  the  state,  the  flowers, 
in  general  appearance  like  those  of  the  flax,  are  white  and  the 
flowering  stems  and  leaves  arise  from  a  slender,  scaly  rootstock. 
At  the  base  of  the  plant  are  borne,  on  recurved  pedicels,  curi- 
ous small  flowers  which  do  not  open,  but  mature  their  fruits, 
after  close-pollination,  from  stamens  developed  side  by  side 
with  the  fruit-rudiment.  The  other  wrood-sorrels  have  violet 
flowers  in  one  species  and  yellow  flowers  in  the  other.  The 
violet-flowered  wood-sorrel  comes  from  a  brown  bulb  not  un- 
like the  bulbs  of  certain  lily-like  plants.  For  some  reason 
bulbs  are  but  rarely  produced  by  plants  belonging  to  the  high- 
est class.  The  violet  wood-sorrel  is,  however,  one  of  the  excep- 
tions. The  yellow  wood-sorrel  is  much  more  branched  above 
ground  than  the  others.  Its  leaflets  are  sensitive  to  the  touch 
and  if  rubbed  for  a  moment  with  the  fingers  they  will  close. 
The  yellow  wood-sorrel  forms  slender  pods;  the  white  wood- 
sorrel  produces  short  and  rounded  pods,  while  the  pods  of  the 
violet  wood-sorrel  are  ovoid. 

Flax.  Of  flax  there  are  in  Minnesota  three  wild  species  not 
very  easy  to  distinguish  from  each  other.  In  one,  the  flowers 
are  blue  like  those  of  the  cultivated  flax,  which  sometimes 
escapes  as  a  weed.  The  wild  blue  flax  may,  however,  be  known 
by  the  capsule  which  in  fruit  is  much  longer  than  the  calyx. 
Besides  this  variety  there  are  two  wild  flaxes  in  which  the  flow- 
ers are  yellow.  They  may  be  distinguished  by  the  length  of 
their  capsules.  In  the  grooved  yellow  flax  the  capsules  are 
from  one  to  one  and  a  half  lines  long,  while  in  the  stiff  yellow 
flax  they  are  from  two  to  two  and  a  half  lines  long.  Further- 
more, in  the  grooved  yellow  flax  the  upper  part  of  the  stem 
is  clearly  grooved,  while  in  the  stiff  yellow  flax  the  grooving 
is  not  distinct.  Flax  is  cultivated  for  fibre  and  for  seeds.  From 
the  seeds  linseed-oil  is  manufactured,  and  from  the  fibre  linen 
is  made. 

Nasturtiums.  Nasturtiums,  with  their  pretty,  round,  shield- 
shaped  leaves,  are  favorite  plants  in  borders  and  window-gar- 
dens in  all  parts  of  the  state.  The  plant,  however,  is  not  a 
native.  Perhaps  the  most  interesting  thing  about  it  is  the  great 
sensitiveness  of  its  leaves  to  the  direction  from  which  they  are 


Minnesota  Plant  Life. 

illuminated.  A  plant  placed  in  a  window  will  within  a  short 
time  incline  all  its  leaves  so  that  their  surfaces  are  perpendic- 
ular to  the  rays  of  sunlight.  If  the  pot  is  now  turned  around, 
in  a  short  time  the  leaves  will  slowly  swing  back  and  accom- 
modate themselves  to  the  new  direction  from  which  the  light 
is  shining. 

Prickly  ashes.  The  rue  family  is  represented  in  Minnesota 
by  two  shrubs.  One,  the  prickly  ash,  is  abundant  throughout 
the  southern  part  of  the  state,  extending  as  far  north  as  Leech 
lake.  The  other,  known  as  the  three-leaved  ash,  three-leaved 
elm  or  hop  tree,  is  reputed  to  occur  in  southeastern  Minnesota. 
The  prickly  ashes  sometimes  grow  into  small  trees.  Their 
leaves  are  alternate,  resembling  those  of  the  common  ash  trees, 
and  there  are  from  five  to  eleven  leaflets  in  each  leaf.  The 
flowers  are  borne  in  little  clusters,  appearing  in  the  early  spring 
before  the  foliage,  or  while  the  leaves  are  beginning  to  emerge 
from  the  buds.  The  flowers  are  green  and  of  small  size.  They 
mature  into  black,  egg-shaped  capsules,  each  containing  one 
or  two  black  and  glistening  seeds.  The  twigs  of  this  plant 
are  armed  with  thorns.  Prickly  ashes  are  common  on  hillsides, 
along  rivers  and  at  the  edges  of  oak  woods. 

Three-leaved  elms.  The  three-leaved  elm  has  a  fruit  very 
similar  in  appearance  to  that  of  the  slippery  elm,  though  the 
plants  are  not  particularly  related  to  each  other.  The  leaves 
are  made  up  of  three  leaflets,  and  the  fruit  has  a  decidedly  bitter 
taste,  quite  different  from  that  of  a  true  elm  fruit. 

Milkworts.  The  polygala  family  produces  some  small  herbs 
known  as  polygalas,  milkworts  and  snakeroots.  The  Seneca 
snakeroot  is  gathered  in  quantities  on  account  of  the  medicinal 
value  of  the  rootstock.  These  plants  may  be  recognized  by 
their  flowers,  generally  in  racemes  or  spikes,  but  in  some  in- 
stances becoming  condensed  into  heads,  and  by  the  three  petals 
united  into  a  tube  which  is  deeply  cleft  on  one  side.  Two  of 
the  sepals  are  larger  than  the  other  three  and  there  are  usually 
eight  stamens.  The  fruit  is  a  small  capsule  and  the  seeds  have 
peculiar  appendages. 

Spurges.  Fifteen  species  of  spurges  occur  in  Minnesota. 
Most  of  them  are  mat-plants,  forming  disks  of  much  branched 
vegetation  similar  in  appearance  to  the  carpetweeds  and  purs- 


308  Minnesota  Plant  Life. 

lanes.  Some  of  them,  however,  are  erect,  as,  for  example,  the 
very  beautiful  "snow-on-the-mountains,"  famous  for  the  pure 
white  borders  of  the  leaves.  This  is  also  known  as  the  white- 
bordered  spurge.  Many  of  the  mat  spurges  which  have  been 
alluded  to  are  common  along  railway  tracks  and  roadsides.  All 
of  them  have  a  milky  juice,  and  in  Minnesota,  a  mat-plant  with 
a  milky  juice  is  pretty  certain  to  be  a  spurge.  The  different 
kinds  of  spurges  are  marked  by  the  different  sizes  and  shapes 
of  the  leaves,  the  smoothness  or  hairiness  of  the  stem,  and  the 
surface  of  the  seeds.  One  erect  type,  rather  common  in  the 
western  part  of  the  state,  is  known  by  its  red  seeds  sculptured 
over  with  a  fine  network  marking.  Another,  the  flowering 
spurge,  is  a  very  deceptive  plant  to  the  amateur  botanist.  It 
seems  to  have  clusters  of  flowers  about  the  size  of  flax  flowers, 
arranged  in  loose,  flat-topped  terminal  clusters.  But  each  of 
the  flower-like  areas  is  in  reality  itself  a  cluster  of  flowers  and 
the  four  or  five  white  petal-like  leaves  are  not  really  parts  of 
the  flower,  but  are  bracts  surrounding  the  clusters.  Like  the 
other  spurges,  this  plant  may  be  recognized  by  its  milky  juice. 
It  cannot  well  be  mistaken  for  other  milky-juiced  forms,  such 
as  milkweeds  or  wild  lettuce,  but  it  might  be  mistaken  for 
one  of  the  dogbanes,  from  which  it  differs,  however,  in  the 
whorl  of  leaves  standing  at  the  base  of  the  flowering  area  of  the 
stem.  Besides,  the  real  structure  of  the  flowers  is  altogether 
different,  as  may  be  learned  by  close  observation. 

Water-starworts.  The  water-starworts  or  water-fennels  are 
very  small,  insignificant  herbs  found  growing  on  mud-flats,  or 
submerged  in  flowing  water,  or  in  ponds.  Three  varieties  occur 
in  Minnesota,  all  of  them  with  low  slender  stems  and  opposite 
leaves  with  flowers  in  their  axils.  In  one  kind,  which  grows  in 
flowing  water,  the  leaves  are  linear  and  about  half  an  inch  long. 
In  another,  which  may  grow  in  the  water  or  upon  the  mud, 
the  leaves  are  ordinarily  spoon-shaped,  while  in  still  another  they 
are  ovate.  In  all  of  them,  however,  the  linear  type  of  leaf  may 
prevail  and  it  is  then  very  difficult  to  tell  them  apart.  Tiny 
green  plants  found  growing  on  mud-flats  or  submerged  in  the 
water  may  be  classified  as  water-starworts,  if  they  have  opposite 
leaves  with  an  inconspicuous  bud-like  flower  in  the  axil  of 
each. 


Minnesota  Plant  Life. 


309 


The  twentieth  order  includes  the  crowberry  family;  the 
sumacs,  poison-oak  and  poison-ivy;  the  false  mermaids;  the 
horse-chestnuts,  maples,  box-elders;  and  the  touch-me-nots, 
together  with  the  hollies,  bittersweets,  wahoos  and  bladdernuts 
besides  some  other  families  not  represented  in  Minnesota. 

Crowberries.  Crowberries  are  heath-like  shrubs  and  re- 
semble diminutive  yews.  Their  branches  are  generally  not 
more  than  eight  to  twelve  inches  in  length.  Each  branch 
is  covered  with  densely  crowded  leaves  of  an  evergreen  as- 
pect and  with  the  margins  rolled  over  toward  the  under  side. 
The  plants  generally  grow  in  tufts,  forming  large  mats.  The 
crowberries  are 
rather  rare  in 
Minnesota,  but 
are  known  to 
occur  on  the 
north  shore  of 
Lake  Superior 
and  in  Aitkin 
county  and 
along  the  in- 
ternational 
boundary.  The 
flowers  are  in- 
co  nspicuou  s, 
developed 
in  the  axils  of 
some  of  the 
leaves  toward 

the  tips  of  the  branchlets.  The  fruit  is  a  black  stone-fruit,  less 
than  half  an  inch  in  diameter.  This  curious  little  shrub  is 
unlike  any  other  in  the  state.  It  cannot  be  mistaken  for  a  yew 
because  in  that  the  fruits  are  scarlet. 

False  mermaids.  The  false  mermaids  are  odd  little  herbs 
with  pinnate  leaves  and  deeply  lobed  fruits  cleft  into  from  two 
to  five  nutlets.  They  are  marsh  plants  and  grow  as  slender, 
more  or  less  prostrate  herbs,  with  solitary  white  flowers,  trian- 
gular in  shape.  No  other  plant  in  Minnesota  resembles  the 
false  mermaid. 


FIG.  150.     Sumac  bushes,  with  golden-rods  in  foreground  and 
pies  in  background.    After  photograph  by  Williams. 


3io 


Minnesota  Plant  Life. 


Sumacs  and  poison-elders.  The  sumacs  include  seven  va- 
rieties and  are  met  with  pretty  commonly  throughout  the  state. 
With  one  exception — the  fragrant  sumac — they  are  abundant. 
They  are  shrubs  with  pinnate  leaves  and  invite  attention  by 
their  large  panicles  of  small  stone-fruits,  bright  red  in  color  in 
some  of  the  varieties,  and  gray  or  white  in  others.  The  innoc- 
uous varieties  of  sumac,  of 
which  there  are  four  or  five 
in  the  state,  may  be  recog- 
nized when  in  fruit  by  the 
massive  red  clusters.  The 
leaves  are  made  up  of  from 
nine  to  thirty  one  leaflets, 
except  in  the  fragrant  su- 
mac, which  bears  three- 
leafleted  leaves  and  much 
smaller  clusters  of  stone- 
fruits.  The  poisonous  va- 
rieties may  be  avoided  by 
noting  their  gray  or  white 
stone-fruits.  There  are  two 
of  these,  the  poison-elder 
(poison-sumac,  poison-dog- 
wood, poison-ash  or  poison- 
oak)  and  the  poison-ivy, 
both  extremely  unpleasant 
to  come  in  contact  with. 
The  poison-elder  grows  for 
the  most  part  in  swamps 
and  is  pretty  abundant 
among  tamarack  through- 
out the  northern  and  central 

FIG.  151.     Poison-sumac.     After  Chesnut.     F.  B.  86,     portions      of     the      State         It 
U.  S.  Dept.  Ag.  .    ' 

becomes  more  rare  in  the 

southern  and  western  districts.  When  in  fruit  it  is  easily  rec- 
ognized by  the  production  of  panicled  currant-bunch-shaped 
clusters  of  gray  stone-fruits.  The  leaves  are  composed  of  about 
seven  leaflets  arranged  in  pinnate  fashion.  From  the  shape  of 
its  leaves  this  plant  is  also  called  the  poison-ash,  and  it  is  known 


Minnesota  Plant  Life. 


in  some  localities  as  the  poison-dogwood.  Farther  south  the 
plants  reach  a  height  of  twenty  to  twenty  five  feet  and  are 
small  trees,  but  in  Minnesota  the  poison-elder  rarely  exceeds 
from  eight  to  twelve  feet.  This  plant  is  much  more  irritating 
than  the  poison-ivy  and  is  the  cause  of  many  of  the  severe  cases 
of  skin-inflammation  in  the  autumn — the  season  when  it  is  most 
virulent. 

Poison-ivy.  The  poison-ivy,  with  currant-bunch  clusters  of 
gray  fruit,  like  those  of  the 
poison-elder,  differs  from  the 
latter  in  being  a  low  bush  or 
woody  vine,  in  one  variety 
climbing,  but  bushy  in  another. 
The  leaves  are  made  up  of 
three  leaflets,  resembling 
somewhat  the  leaves  of  the 
wake-robin  or  trillium.  Poi- 
son-ivy in  fruit  should  not  be 
mistaken  for  any  other  Minne- 
sota plant,  but  careless  observ- 
ers sometimes  take  for  it  the 
woodbine,  a  member  of  the 
vine  family  in  which  the  leaves 
are  made  up  of  five  leaflets. 
Both  the  poison-elder  and  the 
poison-ivy  secrete  a  highly 
poisonous  volatile  oil  which 
rises  in  an  invisible  mist  from 
the  foliage  of  the  plant.  It  is 
often  not  even  necessary  to 
have  handled  the  plant  for 
symptoms  of  poisoning  to  de- 
velop. Merely  approaching  within  a  few  feet  of  it  will  often 
suffice.  One  can  understand  how  this  is  possible  by  noticing 
the  distance  at  which  he  can  smell  the  perfumes  arising  from 
sweet-scented  foliage  or  flowers,  as  for  example,  from  the  worm- 
woods or  the  magnolias.  Just  as  the  air  is  permeated  in  the  one 
instance  by  the  perfume,  may  it  in  the  other  be  filled  with  the 
poisonous  exhalations.  Among  the  antidotes  for  ivy  or  elder 


FIG.  152.     Poison-ivy.    After  Chesnut.    F.  B. 
86,  U.  S.  Dcpt.  Ag. 


312  Minnesota  Plant  Life. 

poisoning  are  the  acetates  of  lead  or  zinc,  made  into  concen- 
trated solutions  and  applied  with  a  cloth  or  sponge  as  a  wash 
for  the  affected  parts.  Salol  is  also  a  specific. 

The  ordinary  innocuous  sumacs  are,  from  their  brilliant 
autumnal  tints,  very  beautiful  shrubs  of  the  Minnesota  copses 
and  hillsides.  The  poisonous  varieties  do  not  show  the  rich 
hues  of  their  harmless  relatives. 

Hollies.  One  sort  of  holly  bush  is  not  uncommon  in  the 
state.  It  is  a  shrub,  usually  six  to  twelve  feet  in  height  in  Min- 
nesota, with  leaves  shaped  like  plum  leaves,  but  rather  thick, 
dark  green  and  smooth  above,  turning  black  in  autumn.  Hence 
the  bush  is  sometimes  called  black  alder.  In  late  autumn,  clus- 
ters of  red  stone-fruits,  spherical  in  shape,  are  found  at  the  bases 
of  the  leaves.  The  flowers  are  of  two  sorts,  staminate  flowers 
devoid  of  pistils  and  perfect  flowers  with  both  stamens  and  pis- 
tils. The  Minnesota  variety  of  holly  has  not  the  spiny  leaves 
of  the  Christmas  holly,  but  its  stone-fruits  are  of  the  same 
brilliant  red,  though  rather  smaller.  Another  kind  of  holly, 
the  mountain  holly,  with  grooved  stone-fruits  or  capsules  and 
smaller  smooth-margined  leaves,  occurs  in  the  southeastern  part 
of  the  state.  The  deep  longitudinal  grooves  in  the  fruit  serve 
to  distinguish  it  from  the  swamp  holly.  Hollies  and  poison- 
elders  very  commonly  grow  close  together  among  the  trees  of 
tamarack  swamps,  and  those  gathering  holly  berries  in  the  au- 
tumn will  do  well  to  observe  any  suspicious  elder-leafed  shrubs 
that  are  near  by,  and  avoid  them. 

Climbing  bittersweets  and  wahoos.  One  species  of  bitter- 
sweet and  two  wahoos  represent  their  family  in  Minnesota. 
The  bittersweet  is  a  twining  vine,  often  climbing  up  the  trunks 
of  small  trees  in  the  woods  and  displaying  its  stem  along  their 
branches  twenty  feet  or  more  from  the  ground.  The  leaves 
are  alternate  and  shaped  somewhat  like  plum  leaves.  The  flow- 
ers are  produced  in  racemes  and  mature  their  fruits  as  orange- 
colored,  spherical  capsules,  half  an  inch  or  less  in  diameter. 
These  fruits  split  open  by  three  clefts  in  autumn  and  show  a 
red,  pulpy  structure  inside. 

The  wahoo  or  spindle-tree,  sometimes  known  also  as  burn- 
ing-bush, is  a  shrub  from  six  to  twelve  feet  in  height  in  Min- 
nesota. The  leaves  are  plum-shaped,  the  flowers  are  purple, 


512 


Plant  Lif 


ll 


00, 


3  » 
Str 


l 

II 

Oj    0 

cr^ 

S-S 
ft-  1 


S  E 

fr  a 

» 


e  cr 

e  a 


Ba 


n  is  als<  -lie. 

e,    from   their 
ibs  of  the  Minnesota 
•  poisonous  varieties  do  not  show  the 
tnless  relatives. 

e  sort- of  holly  bush  is  not  uncommon  in 
lally  six  to  twelve  feet  in  height  in  . 
ves  shaped  like  plum  le  ather  t' 

smooth  above,  turns; 

times  called  black  a  ...    , 

•  fruits,  spherica' 

The  flowers  are  of  t  aate  flo- 

and  perfect  flo\vers  with  both  stamens  and 
;a  variety  of  holly  has  not  the  spiny  leaver 
.  but  its  stone-fruits  are  of  the  same 
1,  thougl.  uller.      Another  kind  of   holly, 

iin  holly,  wii  :its  or  capsules 

>oth-margine< 
.  The  deep 
ish  it  from  i 
common 


bittersweets  e  species  of  bitter- 

nt  their  family  in  Minnesota. 
e,  often  climbing  up  the  tru 
displaying  its  stem  along  their 
i'rbm  the  ground.     The  le; 
:at  like  plum  lea 

sture  their  fruits  as  orange- 
inch  or  less  in  diameter. 
in  autumn  and  she 


n  also  as  bv 
heigfht  in  Iv; 


Minnesota  Plant  Life.  ->,-, 

borne  in  axillary  cymes,  the  fruits  are  singular,  deeply-lobed, 
three  or  four-parted  capsules.  When  the  capsules  split  along 
the  sides,  a  red,  fleshy  mass  is  shown  within  similar  to  that 
observed  when  the  bittersweet  capsules  open.  The  cliinl .in- 
habit of  the  bittersweet  serves,  however,  at  once  to  distingui>h 
it  from  the  common  wahoo.  A  rare  species  of  wahoo  is  a 
trailing  shrub. 

Bladdernuts.  Bladdernuts  are  branching  shrubs  with  pe- 
culiar, large,  deeply  three-lobed  bladdery  capsules.  The  leaves 
are  made  up  of  three  leaflets  and  the  clusters  of  flowers  arise 
in  their  axils.  These  plants  may  be  readily  recognized  by  the 
capsules  which  resemble  three  small  pea-pods  blended  together 
by  their  backs  and  separate  at  their  tips.  They  are  not  uncom- 
mon in  the  southern  part  of  the  state,  where  they  inhabit  the 
edges  of  woods. 

Maple  trees.  Seven  kinds  of  maple,  including  the  box-elder, 
occur  in  Minnesota.  These  are  the  soft  maple,  the  red  maple, 
the  sugar  or  hard  maple,  the  black  maple,  the  moosewood 
maple,  the  mountain  maple,  and  the  ash-leaved  maple  or  box- 
elder.  All  of  these  plants  may  be  known  by  their  production 
of  two-lobed  fruits  provided  with  wings.  The  fruits  separate 
into  halves  when  ripe  and  each  half,  furnished  with  its  wing, 
obtains  distribution  by  the  wind.  The  box-elder  is  the  only 
Minnesota  maple  with  pinnate  leaves.  In  this  plant  each  leaf 
is  made  up  of  from  three  to  seven  leaflets.  The  other  maples, 
in  which  the  leaves  are  simple,  may  be  distinguished  by  their 
flowers,  leaves,  bark  and  fruits.  The  soft  maple  and  the  red 
maple  display  their  flowers  before  the  leaves  emerge  from  the 
buds  and  are  among  the  earliest  flowering  Minnesota  species. 
The  flowers  of  the  common  soft  maple  have  no  petals  and  are, 
therefore,  rather  inconspicuous,  while  the  flowers  of  the  red 
maple  have  showy  red  or  yellow  petals.  The  sugar-maple, 
or  hard  maple,  and  the  black  maple  form  the  flowers  on  long 
drooping  stalks  and  at  the  same  time  that  the  leaves  unfold. 
The  leaves  of  the  sugar-maple  are  smooth  on  the  under  side, 
while  in  the  black  maple  they  are  hairy  below,  usually  over  the 
whole  surface  and  always  on  the  veins.  The  moosewood  maple 
and  mountain  maple  open  their  flowers  in  terminal  racemes  after 
the  leaves  have  unfolded.  In  the  moosewood  maple  the  ra- 
cemes are  drooping,  while  in  the  mountain  maple  they  are  erect. 


3*4 


Minnesota  Plant  Life. 


Of  these  plants,  the  soft,  red,  hard  and  black  maples  are  large 
and  handsome  trees,  while  the  moosewood  and  mountain  maples 
are  small  trees  or  shrubs.  The  black  maple  has  a  rough  black 
bark.  The  sugar-maple  is  utilized  in  the  manufacture  of  sugar, 
obtained  by  boiling  down  its  copious  sap  in  the  springtime. 
The  red  maple  has  scarlet  or  crimson  bark  on  the  younger  trees. 
The  soft  maple  has  whitish  bark  with  leaves  more  notched  than 
in  the  hard  or  black  varieties.  The  moosewood  maple  has 
leaves  with  two  deep  notches  making  three  sharp  lobes  toward 
the  end.  All  the  lobes  are  about  equal  in  size.  The  mountain 

maple  has  leaves 
similarly  three- 
lobed,but  the  middle 
lobe  is  much  the 
largest. 

Soft  maples.  The 
soft  maples  are 
abundantly  planted 
in  Minnesota  for 
shade  trees,  for 
which  purpose,  how- 
ever, they  are  not  so 
valuable  as  hard  ma- 
ples. Under  favor- 
able conditions  they 
grow  to  be  large 
trees,  over  a  hun- 
dred feet  in  height.  The  branches  are  brittle  and  many  of  them 
are  markedly  pendulous  like  the  branches  of  the  weeping  wil- 
lows. The  leaves  are  five-lobed,  bright  green  above  and  whit- 
ish or  silvery  below.  In  autumn  they  turn  yellow.  The  flowers 
are  produced  in  little  heads  on  short  lateral  branches,  and  there 
are  two  kinds,  staminate  and  pistillate,  often  borne  on  the 
same,  but  sometimes  on  different  trees.  The  fruits  hang  on 
slender,  drooping  stems,  and  very  often  one  side  of  the  fruit 
fails  to  mature.  As  soon  as  the  seeds  fall  to  the  ground,  or 
the  next  season,  they  may  germinate,  and  the  seedlings  develop 
their  first  leaves  and  terminal  bud  during  June.  Maple  wood, 
from  this  species,  is  hard  and  is  used  in  the  manufacture  of 


FIG.  153.    lyeaves  and  flowers  of  the  sugar-maple.     After 
Atkinson. 


Minnesota  Plant  Life. 


315 


woodenware  or  furniture.  Soft  maples  are  abundant  through- 
out the  southern  part  of  Minnesota  and  extend  north  to  Bel- 
trami  county. 

Red  maples.  The  red  maple  commonly  occurs  in  Minne- 
sota as  a  bush  or  low  tree,  but  may,  under  the  best  conditions, 
reach  a  height  of  over  a  hundred  feet.  The  bark  is  of  a  dark 
gray  color.  The  leaves  are  whiter  below  than  above,  and  in 
autumn  exhibit  beautiful  hues  of  scarlet  and  orange.  The 
flowers  are  borne  much  as  in  the  soft  maple  and  the  fruits  some- 


Fio.  154.    A  grove  of  sugar-maples.     Near  I^ake  Minnetonka.    After  photograph  by  Mr.  E.  C. 

Mills. 

what  resemble  those  of  the  latter  species,  though  the  wings  are 
more  incurved.  The  red  twigs,  brilliant  autumnal  color,  and 
more  conspicuous  flowers  distinguish  easily  this  maple  from  the 
soft  maple.  Its  wood  is  heavy  and  one  variety  of  it,  known 
as  curly  maple,  when  polished  is  very  beautiful.  In  Minnesota 
the  red  maple  is  one  of  the  earliest  trees  to  assume  the  autumn 
tints,  and,  with  the  sumacs,  gives  a  vivid  color  to  hillsides 
before  the  deep  red  of  the  scarlet  oaks  appears. 

Sugar-maples.      The  sugar-maple  is  a  large,  round-headed 
tree,  sometimes  growing  in  Minnesota  to  a  height  of  seventy 


Minnesota  Plant  Life. 


five  or  eighty  feet,  and,  under  the  most  favorable  conditions, 
to  nearly  twice  this  height.  On  the  trunk  the  bark  is  of  a  light 
gray  color,  while  on  young  twigs  it  is  orange  or  yellow-brown. 
The  leaves  are  darker  green  than  those  of  the  soft  maple  and 
assume  a  variety  of  colors  in  the  autumn,  some  trees  turning 
scarlet,  others  crimson,  others  yellow,  If  a  particular  tree  is 
yellow  one  year  it  will  be  yellow  the  next,  the  tint  of  the  autumn 
foliage  being  apparently  an  individual  habit.  The  pistillate 
flowers  are  more  commonly  borne  towards  the  tips  of  their 

branchlets,  while  the  staminate 
flowers  are  on  the  sides,  and  lower 
down.  The  wood  is  strong  and 
tough,  more  valuable  than  that  of 
any  other  common  maple.  It  is 
useful  for  fuel  and  is  employed  in 
the  manufacture  of  flooring,  furni- 
ture, tool-handles  and  portions  of 
machinery.  Bird's-eye  maple  and 
a  form  of  curly  maple  are  obtained 
from  diseased  trunks  of  the  sugar- 
maple.  It  is  this  species  which  sup- 
plies the  greater  part  of  the  maple 
sugar,  though  that  is  also  made 
from  the  black  maple  and  from  the 
moosewood  by  the  Indians  of  north- 
ern Minnesota.  The  sugar  obtained 
from  the  sugar-maple  is  of  a  some- 
what better  quality,  however,  than 
that  derived  from  the  other  species. 

Black  maples.  The  black  maple  is  very  closely  related  to 
the  sugar-maple  and  is  possibly  only  a  variety  of  it. 

Moosewood  maples.  The  moosewood  maple  occurs  in  Min- 
nesota as  a  small  and  bushy  tree  with  red-brown  twigs  and 
striped  bark  of  a  brown  color.  The  leaves  are  smooth  on  both 
sides,  turning  yellow  in  autumn.  The  flowers  open  in  late 
spring,  the  sterile  and  the  fertile  being  produced  on  the  same 
plant,  but  in  different  clusters.  The  wood  is  light  and  soft. 
The  name  "moosewood"  is  applied  from  the  habit  which  the 
moose  have  of  chewing  the  young  twigs  on  account  of  their 
sweet  juices. 


FIG.  155.     Moosewood  maple.    After 
Britton  and  Brown. 


Minnesota  Plant  Life. 


317 


Mountain-maples.  The  mountain-maple  in  Minnesota  is  a 
rather  low  shrub.  The  leaves  turn  scarlet  or  orange  in  autumn 
and  the  flowers  are  of  two  sorts,  generally  produced  in  the  same 
cluster,  the  staminate  towards  the  tips  and  the  pistillate  toward 
the  bases.  The  wood  is  soft,  light,  and  of  little  commercial 
value. 

Box-elders.  The  box-elder  grows  as  a  small  tree,  thirty  or 
forty  feet  in  height,  though  farther  south  it  becomes  larger. 
The  bark  is  of  a  brown  or  gray  color;  the  twigs  are  purplish 
with  a  white  bloom.  The  leaves  do  not  show  any  brilliant 
autumn  coloration.  There  are  two  kinds  of  flowers,  staminate 
and  pistillate,  always  borne  on  separate  trees.  The  staminate 
flowers  hang  in  clusters  on 
thread-like  stalks,  while  the 
pistillate  droop  in  loose  ra- 
cemes. The  fruits  mature 
in  autumn  and  often  cling 
to  the  trees  throughout  the 
winter.  When  they  fall  in 
autumn,  as  they  more  com- 
monly do,  the  stems  on 
which  they  were  produced 
remain  until  the  succeeding 
spring,  attached  to  the  twigs 
that  bore  them.  The  wood 
is  soft  and  weak,  but  is  em- 

i  i     •         ,1  f  „    FIG.  156.    Touch-me-not.    After  Britton  and  Brown. 

ployed  in  the  manufacture 

of  some  woodenware  and  for  wood-pulp.  This  is  a  favorite 
shade  tree  along  the  streets  of  Minnesota  towns.  When  grow- 
ing wild  it  is  to  be  looked  for  especially  beside  streams  and  in 
low  woods. 

Buckeyes.  The  horse-chestnut  family  is  represented  in  Min- 
nesota by  the  buckeye,  a  plant  which  is  probably  introduced  into 
the  state  by  the  agency  of  man  and  is  nowhere  abundant,  though 
it  occurs  as  if  native  in  a  few  southeastern  localities.  It  is  a 
small  tree  with  long-stemmed  leaves  made  up  of  about  five 
willow-leaf-shaped  leaflets.  The  flowers,  borne  in  terminal 
panicles,  are  of  a  yellow  color,  not  so  striking  in  their  appear- 
ance as  those  of  the  horse-chestnut.  The  fruit  is  a  spiny,  spher- 


318  Minnesota  Plant  Life. 

ical  capsule,  an  inch  or  so  in  diameter,  becoming  smoother  with 
maturity.  The  seeds,  of  which  one  or  two  are  produced  in  a 
fruit,  are  large  and  have  glistening  coats.  The  wood  is  soft 
and  white  and,  in  Ohio  and  Indiana  where  the  tree  is  more 
abundant  than  farther  northwest,  is  used  in  the  manufacture 
of  woodenware. 

Touch-me-nots.  There  are  two  species  of  touch-me-nots  in 
Minnesota.  Both  of  them  are  shade-loving  plants,  and  grow 
in  swamps,  damp  woods  and  ravines,  where  the  light  is  not  too 
strong.  Their  stems  are  translucent  and  one  can  see  the  fibrous 
threads  through  the  skin.  The  leaves  are  very  thin,  of  ovate 
shape,  and  with  toothed  margins.  They  wilt  almost  immediately 
if  removed  from  their  stem.  The  flowers  are  colored — in  one 
variety,  orange  speckled  with  brown,  in  the  other  pale  yellow— 
and  two-sided,  looking  a  very  little  like  snapdragon  flowers, 
to  which,  however,  they  are  not  related.  The  fruit  is  an  ob- 
long or  slender  capsule  of  a  bright  green  color  and  succulent 
when  ripe.  If  pressed  gently  between  the  thumb  and  finger, 
or  if  brushed  against,  the  fruit  splits  violently  into  strips 
which  coil  together,  ejecting  the  seeds  with  explosive  force. 
The  touch-me-nots  are  perfect  examples  of  the  adaptational 
group  of  plants  known  as  shade  plants.  They  are  pale  in  color 
throughout,  with  thin,  rather  large  leaves  and  an  abundance  of 
moisture  in  their  tissues.  They  do  not  secrete  purple  coloring 
substances  in  marked  quantities  either  in  their  leaves  or  in  their 
stems.  They  are  very  abundant  in  Minnesota  near  rivulets,  in 
wooded  ravines,  in  tamarack  swamps  and  around  springs. 


Chapter  XXXII. 

From  Buckthorns  to  Prickly-pears. 


The  twenty  first  order  includes  two  families,  the  buckthorns, 
of  which  there  are  two  species,  and  the  vines,  with  four  grape- 
vines and  one  Virginia  creeper. 

Dwarf  alders.  The  alder-leafed  buckthorn,  or  dwarf  alder, 
is  a  shrub  found  growing  in  swamps  and  recognized  by  its 
plum-shaped  alternate  leaves,  in  the  axils  of  which  small  flowers 
arise.  There  are  no  petals,  and  the  calyx  is  urn-shaped  with 
four  or  five  teeth  at  the  margin.  The  stamens  are  borne  on 
the  calyx  between  its  notches.  The  fruit  is  berry-like,  contain- 
ing three  nutlets  within.  The  character  of  the  fruit  and  the 
structure  of  the  flower  easily  distinguish  this  shrub  from  others 
which  might  be  mistaken  for  it. 

New  Jersey  teas.  Besides  the  buckthorn,  there  are  two 
varieties  of  New  Jersey  tea  or  redroot,  one  of  which  is  pretty 
abundant  throughout  the  state,  while  the  other  is  less  com- 
mon. These  plants  are  small  shrubs,  the  two  species  be- 
ing distinguished  by  the  shapes  of  the  leaves.  One,  the 
American  redroot,  has  ovate,  while  the  other  produces  lance- 
head-shaped  oblong  leaves.  In  both  varieties  the  flower  is  very 
similar  to  that  of  the  buckthorn.  The  calyx-parts  are  fused 
together  at  their  base  and  have  five  notches  at  the  margin. 
Between  these  notches  the  stamens  are  borne,  five  in  number, 
while  under  each  stamen  arises  a  curious  ladle-shaped  petal  of 
a  white  color.  The  black  fruits  are  dry  and  deeply  three- 
grooved,  and  when  mature  they  separate  longitudinally  into 
three  hard  nutlets.  The  American  redroot  is  more  abundant 
in  dry  woods,  while  the  smaller  redroot  prefers  rocky  places, 
barren  soil,  dry  hillsides  or  bluffs,  or  the  tops  of  knoJls  in  the 
rolling  prairie.  The  name,  "New  Jersey  tea,"  arises  from  the 
use  of  the  plant  in  place  of  tea  by  American  soldiers  during  the 
Revolution. 


20 


Minnesota  Plant  Life. 


Wild  grapes.  The  wild  grapes  can  scarcely  be  mistaken  for 
any  other  plants,  except,  perhaps,  the  moonseeds,  from  which 
they  are  known  at  once  by  their  more  or  less  pear-shaped  seeds. 


FIG.  157.  _Tree  covered  by  grape-vine.     After  photograph  by  Williams. 

They  are  all  of  them  tendril-bearing,  climbing,  shrubby  vines, 
with  characteristic  maple-like  leaves.  The  flowers  are  either 
altogether  separated,  or  of  two  sorts  on  the  same  plant.  It 


Minnesota  Plant  Life. 

is  not  usual  to  find  among  grapes  what  are  known  as  perfect 
flowers,  with  both  stamens  and  pistils.  The  fruit  is  a  spherical 
berry  of  a  blue  or  purplish-black  color,  edible  and  containing 
from  two  to  four  seeds.  The  four  varieties  of  grapes  in  Min- 
nesota are  the  fox-grape,  the  summer  grape,  the  frost-grape, 
which  is  the  common  one,  and  the  riverside  grape,  which  is 
likewise  abundant  except  along  the  north  shore  of  Lake  Supe- 
rior. The  different  grapes  may  be  discriminated  from  each 
other  by  certain  structural  characters.  The  fox-grape  and  the 
summer  grape  have  leaves  with  cottony  under  sides.  The  other 
varieties  have  leaves  with  smooth,  or  only  slightly  hairy  under 
sides.  In  the  fox-grape  the  berries  are  rather  large,  with  a 
strong  musky  fragrance,  and  the  cotton  on  the  under  sides  of 
the  leaves  is  of  a  brownish  color.  The  summer  grape  has  small 
berries  without  the  musky  fragrance;  and  the  cotton  on  the 
under  side  of  mature  leaves  is  almost  white.  The  riverside 
grape  may  be  distinguished  from  the  other  smooth-leafed  va- 
iety  by  the  bloom  on  its  berries  and  by  its  trailing  or  low  habit 
of  growth,  while  the  frost-grape  climbs  high,  often  swinging 
itself  on  the  branches  of  trees,  and  produces  black  shining 
berries,  ripening  after  frost  and  not  possessing  the  distinct 
bloom  of  the  riverside  grape.  In  all  of  these  vines  the  fruits 
hang  in  panicles  and  droop  from  the  weight  of  the  berries. 

Virginia  creepers..  The  Virginia  creeper  or  woodbine,  is  an 
abundant  plant  in  most  sections  of  the  state.  The  tendrils 
of  this  vine  often  form  little  sucker-like  disks  by  which  they 
attach  themselves  to  walls  or  fences,  making  the  plant  a  desir- 
able climber  in  dooryards  and  about  houses.  The  leaves  are 
composed  of  from  five  to  seven  leaflets,  five  being  much  the 
more  common  number.  The  fruits  are  grape-like,  with  from  one 
to  four  seeds,  and  are  borne  in  forking  clusters  that  stand  erect 
owing  to  the  strong  pedicels  and  smaller  weight  of  the  whole 
as  compared  with  a  bunch  of  grapes.  The  berries  are  not 
edible. 

The  twenty  second  order  includes  six  families  not  represented 
in  Minnesota,  and  in  addition  to  these  the  basswoods,  and  the 
mallows  to  which  the  hollyhock  of  country  gardens  belongs. 

Basswoods.  One  variety  of  basswood,  known  also  as  the 
American  linden  or  whitewood,  is  native  within  the  borders  of 


22 


322 


Minnesota  Plant  Life. 


the  state.  It  is  a  handsome  tree,  reaching  a  height  of  seventy 
feet  or  more,  very  abundant  in  the  hardwood  belt  throughout 
Minnesota,  and  only  less  common  along  streams  and  on  hill- 
sides in  the  northern  woods.  Its  range  extends  to  Thunder 
bay,  Lake  Superior,  and  along  the  international  boundary  to 
Lake  of  the  Woods.  The  trunk  is  rather  slender,  not  more 
than  two  feet  in  diameter  in  the  northern  portions  of  its  range. 
The  leaves  are  large  and  broad,  unevenly  heart-shaped  at  the 
base  and  turning  yellow  in  autumn.  The  flowers  are  produced 
in  cymes  upon  a  stem  that  bears  at  the  base  a  remarkable 


FIG.  158.    Virginia  creeper  on  tree  trunks.     After  Schneck  in  Meehan's  Monthly. 

wing-shaped  bract  which  is  coherent  until  about  its  middle  with 
the  flowering  stem.  The  fruit  is  a  hard  berry,  and  within  it 
are  one  or  more  seeds.  Two  or  more  of  the  berries  are  ma- 
tured in  a  cluster  and  the  stem  of  the  cluster  with  the  adher- 
ent wing-shaped  bract  separates  from  the  tree.  The  centre  of 
gravity  of  the  cluster  and  the  shape  of  the  wing  are  so  exactly 
coordinated  that  the  whole  affair  whirls  through  the  atmos- 
phere, making  of  itself  a  little  parachute.  By  this  means  the 
berries  are  often  distributed  to  a  considerable  distance.  The 
wood  is  pale  brown  in  color,  light,  and  rather  weak.  It  is 


Minnesota  Plant  Life. 


323 


employed  principally  in  the  manufacture  of  wood  pulp  or  paper 
and  in  the  production  of  some  kinds  of  furniture  and  wooden- 
ware.  The  inner  bark,  which  is  papery,  is  used  by  nur-< 
men  to  tie  buds  into  scions.  The  basswood  is  a  very  desir- 
able shade  tree  and  is  frequently  planted  in  dooryards  and 
along  streets.  The  European  basswood  or  linden,  which  ^ives 
the  name  to  the  famous  street  ''Untcr  den  Linden"  of  the  Ger- 
man capital,  is  sometimes  planted  in  the  United  States,  but 
is  not  particularly  abundant  in  Minnesota.  Unlike  the  Amer- 
ican species,  it  has  no  scales  at  the  base  of  the  petals  in  the 
flowrer. 

Mallows.  The  mallowr  family  includes  a  little  group  of  herbs, 
mostly  introduced  from  Europe,  such  as  the  hollyhock,  the 
creeping-charley  or  cheese  plant,  the  velvetleaf,  the  ketmias  or 
rose-mallows  and  some  others.  There  are  a  few  native  species, 
none  of  which  is  very  common.  Among  them  are  the  Collir- 
rhoe  and  false  mallow  of  the  southwestern  corner  of  the  state, 
the  glade-mallowr,  a  rare  plant  of  the  southwestern  section,  and 
the  halberd-leafed  rose-mallow,  found  occasionally  along  the 
Mississippi  river  in  the  vicinity  of  the  Twin  Cities. 

Mallows  may  be  distinguished  from  other  plants  by  the  devel- 
opment in  the  flower  of  large  numbers  of  stamens  all  blended 
together  by  their  bases  into  a  tube  which  surrounds  the  fruit- 
rudiment.  The  latter  has  several  compartments  and  encloses 
one  or  two  seeds  in  each.  The  embryo  is  curved  and  con- 
tains albumen.  Sometimes  the  flowers  are  large  and  shuwy. 
as  in  the  hollyhock,  while  in  other  varieties  they  are  rather 
small.  The  common  round-leafed  mallow  or  creeping-charley, 
also  known  as  cheese  plant,  from  its  disk-shaped  little  fruit- 
bodies,  sometimes  eaten  by  children,  is  a  common  plant  in 
dooryards  and  waste  places.  The  flower  is  like  that  of  the 
hollyhock,  only  much  smaller  and  of  a  pale  blue  color.  The  high 
mallow  is  an  erect  plant  of  biennial  growth,  with  fruits  quite 
similar  to  the  creeping  variety  and  leaves  shaped  like  those  of 
currants.  The  crisp  mallow  has  the  margins  of  the  leaves  crisped 
like  some  varieties  of  lettuce,  while  the  general  shape  of  the 
leaves  reminds  one  very  much  of  the  high  mallow.  The  Cul- 
lirrhoes,  of  which  at  least  one  variety,  and  probably  two.  are  to 
be  found  in  Minnesota,  are  known  also  as  poppy-mallows.  They 


324 


Minnesota  Plant  Life. 


are  herbs  of  the  prairies  and  should  be  looked  for  particularly 
in  the  far  southwestern  portions  of  the  state.  One  of  them 
is  occasionally  found  along  railways  as  far  east  and  north  as 
Minneapolis.  The  two  varieties  of  Callirrhoe  are  distinguished 


FIG.  159.     Basswood  trees.     Shore  of  L,ake  Calhoun.     After  photograph  by  Hibbard. 

by  the  shape  of  their  leaves.  The  triangular-leafed  poppy- 
mallow  has  the  lower  leaves  somewhat  halberd-shaped,  while 
the  other  puts  forth  deep-lobed  round  leaves.  The  flowers  in 
each  of  these  varieties  are  rather  large  and  showy,  purple  in 


Minnesota  Plant  Life. 

o    D 

color,  verging  towards  red.  The  prairie  mallow  resembles 
closely  in  general  appearance  the  poppy-mallows,  but  may  be 
distinguished  by  the  silvery  foliage  and  the  red  flowers.  'The 
glade-mallow  displays  rather  small  white  flowers  in  terminal 
clusters.  The  leaves  are  shaped  very  much  like  those  of  the 
soft  maple,  only  smaller.  The  whole  plant  is  an  erect,  slender 
herb  from  four  to  eight  feet  in  height.  It  has  been  found  in 
damp  woods  in  Goodhue  county,  and  occurs  in  such  localities 
as  far  west  as  Mankato.  The  native  rose-mallow  is  an  herb, 
three  to  five  feet  in  height,  with  leaves  heart-shaped  or  three- 
lobed  on  the  upper  side,  velvety  to  the  touch.  The  flowers  are 
large  and  of  a  pretty  pink  tint,  growing  darker  toward  the 
centre.  In  fruit,  the  calyx  is  inflated  into  a  bladdery  sheath 
not  unlike  that  of  the  ground-cherries.  The  ketmia  is  a  low 
herb  with  deeply-cleft  leaves.  The  flowers  are  large  and  yellow, 
with  purplish  centre,  and  remain  open  but  a  few  hours ;  hence 
the  plant  is  also  known  as  the  flower-of-an-hour.  Like  that  of 
the  halberd-leafed  rose-mallow,  the  calyx  in  this  variety  inflates 
itself  into  a  little  balloon-shaped  bag  around  the  fruit.  Another 
name  for  this  plant  is  black-eyed  Susan.  It  is  rather  abundant 
in  waste  fields  and  vacant  lots  in  the  vicinity  of  St.  Paul  and 
Minneapolis. 

Velvetleafs,  The  velvetleaf,  which  is  sometimes  encountered 
in  the  southern  part  of  the  state,  is  a  large  herb,  often  six  feet 
in  height,  with  leaves  in  size  and  shape  like  those  of  the  linden. 
They  are,  however,  of  a  soft  velvety  texture ;  hence  the  common 
name  applied  to  the  plant.  The  flowers  are  yellow  and  are 
borne  in  the  axils  of  small  leaves  toward  the  ends  of  branches. 
The  twelve  or  more  carpels  which  make  up  the  fruit  are  sep- 
arated from  each  other  by  deep  longitudinal  grooves,  and  the 
appearance  of  the  whole  fruit-body  is  something  like  that  of  a 
circle  of  milk-pitchers  set  close  together  with  their  lips  point- 
ing outward. 

None  of  the  mallows  is  of  any  particular  economic  impor- 
tance. The  hollyhock  and  the  ketmia  are  cultivated  for  orna- 
ment, and  it  is  in  this  family  that  the  marshmallow — a  plant  with 
mucilaginous  root,  used  in  the  manufacture  of  a  popular  con- 
fection— is  grouped. 

The  twenty  third  order  includes  twenty  six  families  of  plants 
without  any  Minnesota  representatives  and  but  three  families 


326  Minnesota  Plant  Life. 

of  which  Minnesota  species  are  known.  Many  of  the  families 
are  small  exotic  groups  of  plants,  but  among  them  are  some 
important  economic  varieties.  The  tea-plant,  a  member  of  the 
tea  family,  cultivated  in  Japan,  China  and  Ceylon,  is  classified 
here, — also  the  camphor  plant,  the  marcgravias,  the  tamarisks, 
the  passion-flowers  and  the  begonias.  The  families  represented 
in  Minnesota  are  the  St.  John's-worts,  with  about  a  dozen 
species,  the  rock-roses,  with  three  or  four  species,  and  the  vio- 
lets, with  about  twenty  species. 

St.  John's-worts.  The  St.  John's-worts  are  herbs  with  oppo- 
site leaves,  which  are  always  marked  with  glandular  dots  or 
small  black  specks.  The  flowers  are  borne  in  panicles  or  cymes 
at  the  apex  of  slender  stems.  In  each  flower  there  are  five  sepals 
and  five  petals,  with  a  number  of  stamens  sometimes  united 
into  clusters.  The  ovary  is  one-chambered,  with  from  three  to 
five  interior  longitudinal  ridges,  along  which  the  numerous  seed- 
rudiments  are  attached.  At  the  top  of  the  capsule,  which  is 
generally  pyramidal-ovoid  in  form,  from  three  to  six  separate 
stigmas  are  borne.  In  some  of  the  Minnesota  varieties  the 
longitudinal  interior  crests  of  the  fruit-rudiment  project  clear 
to  the  centre,  thus  making  a  three-  to  five-chambered  capsule. 
The  flowers  are  regular  in  appearance.  The  different  varieties 
of  St.  John's-worts  may  be  recognized  by  their  general  habit 
of  growth ;  by  the  sizes  and  shapes  of  the  leaves ;  by  the  char- 
acter of  the  flower-cluster,  which,  as  has  been  said,  is  either 
flat-topped  or  panicled;  and  by  the  cross  section  of  the  fruit, 
which  is,  when  mature,  in  all  instances  a  dry  capsule — some- 
times one-chambered,  sometimes  three-chambered  and  some- 
times five-chambered.  In  all  these  the  leaves  are  ovate,  slender 
or  elongated.  One  variety,  the  marsh  St.  John's-wort,  is  found 
only  in  swamps.  It  may  be  recognized  by  its  three-carpeled 
red  capsule. 

Rock-roses.  The  rock-roses  include  three  or  four  plants,  of 
ledges  or  barren  soil,  known  as  frostweeds,  Hudsonias,  pin- 
weeds,  beach  heathers  or  false  heathers.  The  frostweed,  which 
is  a  pretty  common  plant  throughout  the  state,  is  a  woody  herb 
one  or  two  feet  in  height  with  two  kinds  of  flowers, — some  with 
petals  and  clustered  in  terminal  cymes,  the  others  much  smaller, 
without  petals,  almost  sessile  in  the  axils  of  the  leaves.  The 


Minnesota  Plant  Life. 


327 


leaves  are  shaped  like  small  willow  leaves  and  are  covered  with 
a  gray  growth  of  hairs.  The  petaled  flowers  are  light  yellow, 
with  hoary  sepals.  The  fruit  is  a  capsule  ovoid  in  shape  and 
divided  into  three  chambers,  in  each  of  which  is  a  lar-e  number 
of  seeds. 

Beach  heathers.  The  Hndsonia,  or  beach  heather,  is  a  plant 
of  local  occurrence  in  Minnesota,  abundant  on  rocky  islands  at 
Rainy  lake ;  on  Sable  island  at  Lake  of  the  Woods ;  on  sand 
dunes  in  Ancka,  Sherburne  and  Wright  counties ;  and  on  rock 
ledges  in  the  Minnesota  valley,  along  the  St.  Croix  and  lower 
Mississippi.  It  is  a  densely 
tufted  herb,  with  very  small, 
oval  leaves,  covering  each 
other  like  shingles  on  a  roof. 
The  flowers  are  small,  yellow 
and  sessile,  produced  in  clus- 
ters towards  the  ends  of  the 
branches.  The  whole  plant 
has  a  hoary  aspect,  from  the 
minute  white  hairs  with  which 
its  stems  and  leaves  are  cov- 
ered. It  is  an  abundant  dune 
and  crevice  plant  along  the 
international  boundary,  more 
frequent  north  than  south, 
but  found  on  high  rocks  even 
to  the  southern  border  of  the 
state. 

Pinweeds.  The  pinweeds  grow  in  great  abundance  along 
the  St.  Croix  river,  in  open  woods  or  by  the  roadside,  but  are 
less  common  elsewhere  in  the  state.  Minnesota  has  one  or 
two  varieties,  which  may  be  known  by  their  small  simple  leaves, 
in  most  instances  less  than  half  an  inch  in  length,  and  by  their 
large  numbers  of  green  or  purple  flowers  gathered  in  terminal 
panicles.  The  common  Minnesota  variety  is  about  a  foot  in 
height,  slender  and  usually  unbranched  below  the  region  of  the 
flowers.  The  fruits,  when  they  mature,  are  capsules  with  three 
longitudinal  furrows  marking  the  three  carpels  of  which  they 
are  constructed. 


FIG.  160.     Beach  heather.    After  Britton  and 
Brown. 


Minnesota  Plant  Life. 

Violets.  Violets,  of  which  there  are  several  species  in  Min- 
nesota, are  well-known  as  flowers  of  the  springtime  and  are 
remarkable  for  a  number  of  structural  peculiarities  among 
which  may  be  mentioned  the  development  of  their  flowers  singly 
upon  slender,  almost  leafless  stems;  for  the  upper-  and  under- 
sidedness  of  the  flower,  which  in  this  respect  superficially  re- 
sembles the  flowers  of  larkspurs  or  of  orchids;  and  for  the 
production  in  many  varieties  of  small  flowers,  close  to  the  sur- 
face of  the  ground,  incapable  of  opening,  and,  therefore,  pol- 
linated by  their  own  pollen.  The  violets  of  Minnesota  may  be 
divided  into  the  stemless 
and  stemmed  varieties. 
Actually  they  all  have 
stems,  but  in  the  so-called 
stemless  sorts  the  leaves 
and  flower-bearing  axes 
arise  from  short,  erect  or 
prostrate  underground 
stems,  so  that  the  leaves  seem 
tufted  at  the  root,  while  in  the 
stemmed  varieties,  so  named, 
there  is  more  or  less  branching 
of  the  above-ground  portion  of 
the  plant-body.  The  stemless 
varieties  have,  for  the  most 
part,  purple,  lilac  or  white 
flowers,  while  in  the  stemmed  FlG" 16L  Sweet  ^  B.^*'  After  Britton 
violets,  yellow,  white  or  cream- 
colored  flowers  are  also  to  be  found.  Among  the  violets  of 
the  state,  which  are  abundant  and  easily  distinguished,  are  the 
larkspur-leafed  or  prairie  violet,  with  deeply-cut  leaves,  appar- 
ently made  up  of  seven  or  eight  incised  leaflets;  the  meadow 
violet,  with  heart-shaped  leaves;  the  arrow-leafed  violet,  with 
leaves  shaped  like  arrow-heads;  the  bird's-foot  violet,  similar 
in  general  appearance  to  the  prairie  violet,  but  distinguished 
from  it  by  the  beardless  petals;  the  round-leafed  violet,  with 
abundant  closed  flowers,  developed  later  in  the  year  than  the 
open  ones;  the  marsh-violet,  with  its  pale  lilac  petals  marked 
with  darker  veins;  the  sweet  violet,  with  small,  white,  sweet- 


Minnesota  Plant  Life. 

scented  flowers,  abundant  in  two  varieties  in  the  tamarack 
swamps  of  the  state ;  the  kidney-leafed  violet,  with  leaves  of  a 
broad  kidney  shape  and  longer  than  the  flowering  stem;  the 
lance-leafed  violet,  with  leaves  shaped  like  those  of  the  wil- 
low. All  these  belong  to  the  stemless  group.  Among  the 
stemmed  forms  are  Nuttall's  violet,  a  prairie  variety,  with  elon- 
gated, lance-shaped  leaves;  the  halberd-leafed  violet,  with 
leaves  shaped  like  arrow-heads  and  yellow  flowers  like  those  of 
the  preceding  species.  Here,  also,  is  the  common  yellow  violet 
of  the  woods,  with  heart-shaped  and  kidney-shaped  leaves  and 
hairy  stems,  usually  solitary.  Very  similar  to  this  is  the  smooth, 
yellow  violet,  with  narrower  heart-shaped  leaves,  smooth  stems 
and  foliage,  and  clustered  growth.  Related  to  these  yellow- 
flowered  species  is  the  Canada  violet  of  rich  woods,  with  its 
violet  or  whitish  flowers  and  heart-shaped  leaves,  and  the  very 
similar  striped  violet,  with  cream-colored,  white  or  blue  flowers. 
Both  the  latter  have  stems  five  to  fifteen  inches  in  height  and 
not  tufted.  The  Labrador  violet,  with  smaller  heart-shaped 
leaves  and  purple  or  white  flowers,  may  be  distinguished  by  its 
tufted  growth  and  its  production  of  closed  flowers  later  in  the 
season  than  the  ordinary  open  ones.  The  sand  violet  is  known 
by  the  strongly  notched,  slender  stipules  of  the  leaves.  The 
flowers  are  of  violet  color,  the  stems  are  tufted  and  the  leaves 
are  kidney-shaped  or  heart-shaped,  on  stems  longer  than  their 
blades.  The  long-spurred  violet  of  the  Isle  Royale  and  Grand 
Marais  region  may  be  recognized  by  the  slender  spur  of  the 
flower,  in  length  equaling  or  exceeding  the  petals.  Besides 
the  native  forms  the  common  pansy  has  escaped  from  flower- 
gardens  in  the  southern  part  of  the  state  and  sometimes  occurs 
as  a  dooryard  weed. 

Violets  show  in  their  two-sided  flowers  an  adaptation  similar 
to  that  seen  lower  in  the  series  in  the  two-sided  flowers  of  the 
pulse  family  and  of  the  larkspurs,  dr,  still  lower,  in  the  flowers 
of  orchids. 

Prickly-pears.  The  twenty  fourth  order  includes  but  a  single 
family,  the  cacti,  to  which  belong  three  species  of  prickly-pears 
and  the  purple  cactus — rock-plants  of  southern  Minnesota. 
The  cactus  family  is  a  very  extraordinary  group,  in  which  stems 
have  become  fleshy  and  consolidated,  while  leaves  have  been 


330 


Minnesota  Plant  Life. 


modified  into  a  defensive  armor.  These  plants  indicate  a  strong 
adaptation  to  desert  life.  Their  massive,  leafless  stems — leaf- 
less in  the  sense  of  producing  no  ordinary  foliage  leaves — sug- 
gest the  scantiness  of  the  soil-moisture  which  they  are  able  to 
absorb,  and  because  it  is  so-  hard  to  obtain,  they  have  abandoned, 
as  far  as  possible,  their  evaporating  surfaces.  Some  of  them, 
like  the  melon-cacti,  have  not  only  lost  their  foliage,  but  have 
shortened  their  stems  into  spherical  or  ovoid  melon-shaped 
bodies.  They  have  large  roots,  usually  extending  to  a  con- 
siderable distance  in  all  directions  from  the  base  of  the  stem. 

The  strong  defensive  armor  of 
spines,  which  most  varieties 
possess,  suggests  a  danger  to 
which  the  plants  of  an  arid 
region  are  exposed,  owing  to 
the  absence  in  such  districts  of 
abundant  forage  for  herb-eat- 
ing animals.  The  three  Min- 
nesota species  of  prickly-pear 
are  all  of  them  wanderers  from 
the  southwestern  plains,  where 
they  developed  their  peculiar 
characters,  and  now  that  they 
have  entered  the  more  favor- 
able northern  region  they  re- 
tain the  organization  best 
adapted  to  their  original  home. 
After  They  are  not  infrequent  in  the 
Minnesota  valley,  on  ledges  of 

rock  near  New  Ulm  and  Redwood  Falls.  One  variety  occurs 
at  Taylor's  Falls,  in  the  valley  of  the  St.  Croix,  while  two  are 
abundant  on  the  rocks  in  Pipestone  county,  in  the  vicinity  of 
the  old  Indian  quarry.  Perhaps  the  Indians  have  had  some- 
thing to  do  with  their  introduction  from  the  southwest.  The 
three  species  may  be  distinguished  by  their  spines  and  fruits. 
The  western  prickly-pear  produces  a  fleshy  edible  fruit,  free 
from  spines,  from  one  to  two  inches  long,  shaped  somewhat  like 
a  pear,  borne  upon  the  flat,  sinuous  joints  of  the  stem.  In  this 
variety  the  spines  on  the  stem  are  not  numerous.  They  occur 


Minnesota  Plant  Life. 

in  groups  of  from  one  to  four.  The  flowers  are  yellow  with 
a  red  centre.  The  other  two  prickly-pears  have  smaller  fruiu. 
covered  with  spines  and  drier  in  texture.  The  many-spined 
prickly-pear  bears  on  the  flattened  stems  little  masses  of  bristles 
in  tufts,  with  from  five  to  twelve  spines  in  a  group.  They  are 
slender,  from  half  an  inch  to  two  inches  in  length.  The  brittle 
prickly-pear  produces,  on  the  more  egg-shaped  joints  of  the 
stem,  from  one  to  four  central  spines,  varying  from  a  half  to 
one  and  a  half  inches  in  length.  Each  group  of  central  spines 
is  surrounded  by  from  four  to  six  lateral  shorter  prongs.  The 
spines  in  this  species  are  gray,  becoming  black  toward  the  tips, 
while  in  the  many-spined  prickly-pear  the  thorns  are  whitish 
and  not  black  toward  the  tips. 

The  purple  cactus  is  known  by  its  almost  globular,  warty 
and  thorn-covered  stem,  from  one  to  five  inches  in  height, 
arising  either  singly  or  in  tufts.  The  flowers  are  terminal  and 
solitary,  and  are  purple  or  purplish-red.  This  species  is  re- 
ported only  from  the  vicinity  of  Ortonville,  and  probably  does 
not  grow  elsewhere  in  the  state. 


Chapter  XXXIII. 

From  Leatherwoods  to  Dogwoods. 


The  twenty  fifth  order  comprises  eleven  families  that  are  not 
represented  in  Minnesota  and  five  that  are.  Among  the  exotic 
species  are  the  pomegranate,  the  mangrove,  the  myrtles  and 
eucalypti,  the  melostomas,  the  Brazil-nuts  and  a  number  of 
forms  peculiar  to  South  Africa.  In  Minnesota  there  are  found 
one  species  of  the  leatherwood  family,  three  species  of  buffalo- 
berries  and  silverberries,  four  species  of  the  loosestrife  family, 
eighteen  or  twenty  evening  primroses  and  about  six  varieties 
of  water-milfoil. 

Leatherwoods.  The  leatherwood  is  a  shrub  from  two  to 
six  feet  in  height,  not  uncommon  along  streams  in  woods  and 
thickets  throughout  the  greater  part  of  the  state.  It  is  most 
abundant  from  Duluth  to  Lake  of  the  Woods  and  is  not  to 
be  expected  in  the  southwestern  portion  of  the  state,  although 
it  extends  to  New  Ulm  and  Blue  Earth  county.  The  leather- 
wood  has  yellowish-green  twigs,  with  alternate,  broadly  oval, 
entire-margined  leaves.  The  flowers  are  disposed  in  clusters 
of  three  or  four,  appearing  while  the  leaves  are  emerging  from 
the  bud.  The  perianth  is  bell-shaped,  with  eight  stamens  borne 
upon  its  inner  surface  and  protruding  from  the  mouth.  Every 
alternate  stamen  of  the  group  is  longer,  while  the  intermediate 
ones  are  shorter.  The  fruit  is  oval  in  outline,  red  in  color,  and 
about  half  an  inch  in  length.  The  bark  is  poisonous,  acting 
as  a  violent  emetic.  This  shrub  may  be  known  by  the  yellow- 
ish color  of  the  flowers  and  bark,  the  stamens  alternately  longer 
and  shorter,  and  the  red  stone-fruits. 

Buffalo-berries.  The  three  species  of  buffalo-berries  are  sil- 
very shrubs,  particularly  abundant  in  the  Red  river  valley,  in  one 
variety  extending  as  far  east  as  the  north  shore  of  Lake  Supe- 
rior. They  may  all  be  recognized  by  the  curious  scurfy  growth 


Minnesota  Plant  Life.  „- 

on  the  leaves,  which  gives  to  them  a  silvery  lustre  upon  both 
sides  in  the  silverberry  and  silver  buffalo-berry,  but  upon  the 
under  side  alone  in  the  Canada  buffalo-berry.  In  this  latter 
species  a  few  scurfy  shield-shaped  hairs  develop  on  the  upper 
sides  of  the  leaves.  The  silverberry  has  alternate,  oblong 
leaves,  while  buffalo-berries  have  opposite  oblong  leaves.  The 
flowers  are  bell-shaped,  without  corolla.  The  stamens  are  four 
or  eight  in  number,  borne  on  the  inner  surface  of  the  perianth. 
The  silverberry,  which  is  a  most  attractive  and  beautiful  shrub, 
is  silver-colored,  not  only  with  respect  to  the  leaves,  but  over 
the  young  twigs  as  well.  The  fruit  is  oval  in  shape,  silvery  in 
color,  with  a  grooved  stone.  It  ripens  in  August  and  is  edible. 
The  two  varieties  of  buffalo-berries  have  the  same  general 
appearance  as  the  silverberry,  but  are  distinguished  by  their 
opposite  leaves.  In  the  Canada  buffalo-berry  the  leaves  are 
green  on  the  upper  side,  silvery  below,  and  the  twigs  are  not 
thorny.  In  the  silver  buffalo-berry  the  leaves  are  bright  silver- 
colored  on  both  sides  and  the  twigs  are  generally  thorny.  The 
fruit  of  the  Canada  buffalo-berry  is  harmless,  but  flat  and  taste- 
less, and  is  either  of  a  red  or  yellow  color.  The  fruit  of  the 
silver  buffalo-berry  is  of  a  delicious  flavor  and  is  used  by  house- 
wives in  the  Red  river  valley  in  the  manufacture  of  jellies  and 
preserves. 

Loosestrifes.  The  loosestrife  family  includes  some  insignifi- 
cant herbs  with  opposite  leaves  and  small  axillary  flowers,  soli- 
tary in  the  Rotala,  aggregated  in  axillary  clusters  in  the  swamp 
loosestrife,  solitary  again  in  the  true  loosestrife.  The  Amma- 
nias and  water-purslanes  strongly  resemble  the  water-starworts 
in  their  superficial  characters,  but  may  be  distinguished  by  their 
flowers.  They  are,  like  the  water-starworts,  small  aquatic  or 
mud-dwelling  herbs,  with  opposite  leaves  and  axillary  flowers. 
The  water-purslane,  indeed,  has  often  been  mistaken  for  the 
water-starwort  or  water-fennel.  In  the  water-purslanes  and 
Ammanias  the  calyx  is  bell-shaped  with  four  notches  at  the 
margin,  but  in  the  water-starwort  there  is  no  perianth  what- 
ever. The  fruit  of  the  water-purslane  is  a  globular  capsule  with 
two  chambers,  but  that  of  the  water-starwort  is  flattened  and 
deeply  grooved  on  the  flattened  surfaces,  dividing  it  into  two 
distinct  portions.  The  Ammanias  are  larger  herbs  than  the 


334  Minnesota  Plant  Life. 

water-purslane,  but  resemble  the  latter  variety  in  general  char- 
acters. One  variety  of  Ammania  occurs  in  the  state,  and  it 
may  be  recognized  by  the  opposite  linear  leaves,  with  clasp- 
ing bases  and  sharp  tips.  From  one  to  five  flowers,  the  petals 
of  which  soon  fall  from  the  bell-shaped  calyx,  are  produced 
in  the  axils  of  each  leaf.  In  the  water-purslane  the  flowers 
are  solitary  in  the  axils  of  the  tiny,  opposite,  slender  leaves 
and  are  very  small,  green  and  inconspicuous.  The  Rotala 
resembles  an  Ammania  in  its  larger  size,  varying  from  two  to 
six  inches  in  height,  but  has  the  small  axillary  flowers  of  the 
water-purslane.  Unlike  those  of  the  water-purslane,  they  are 
furnished  with  four  small  petals  between  the  four  lobes  of  the 
bell-shaped  calyx.  The  swamp  loosestrife,  which  occurs  in  the 
St.  Croix  valley,  has  stems  from  three  feet  to  ten  feet  in  length 
and  with  whorls  of  willow-shaped  leaves.  The  flowers  are 
nearly  an  inch  in  breadth  and  are  clustered  in  purple  cymes 
in  the  axils  of  the  whorled  leaves.  The  Ly  thrum,  or  purple 
loosestrife,  is  a  plant  of  low  moist  ground,  with  alternate,  stem- 
less,  lance-shaped  or  oblong  pointed  leaves  and  purple  flowers, 
solitary  in  the  upper  axils.  These  plants  are  not  uncommon 
along  low  lake  shores  throughout  the  southern  part  of  the 
state.  A  most  remarkable  peculiarity  of  the  loosestrifes  is 
the  formation  of  very  extraordinary  structures  in  the  cells  of 
the  outer  seed-coats.  In  some  of  the  varieties  each  cell  of  the 
layer  which  makes  up  the  surface  of  the  seed  is  provided  with 
a  curious  cork-screw-like  apparatus,  developed  in  its  cavity  and 
capable  of  being  turned  out  into  the  ground,  where,  together 
with  hundreds  of  other  bodies  of  the  same  nature,  it  assists  in 
drawing  the  seed  into  the  soil. 

Evening-primroses  and  fireweeds.  The  evening-primroses 
— the  family  to  which  the  cultivated  fuchsia  belongs — include 
two  species,  known  as  false  loosestrifes,  from  their  resem- 
blance to  the  true  water-purslanes.  They  have  the  same  op- 
posite leaves,  axillary  flowers  and  general  habits  of  growth. 
There  are,  however,  four  stamens,  and  capsules  with  four  com- 
partments instead  of  two.  These  false  loosestrifes  are  rather 
unusual  plants  of  ditches,  swamps  and  muddy  banks  in  the 
southern  part  of  the  state.  To  the  evening-primrose  family 
belongs  also  the  fireweed  or  willow-herb,  abundant  in  two  va- 


Minnesota  Plant  Life.  335 

rieties,  especially  in  the  northern  part  of  the  state  on  burnt-over 
tracts.  The  fireweed  is  an  erect  herb,  with  purple  flowers  in 
broad  terminal  racemes  and  willow-shaped  leaves  arranged  alter- 
nately upon  the  stem.  The  capsules  split  into  four  sections  and 
release  the  numerous  seeds,  covered  with  cottony  hairs,  by 
means  of  which  they  are  distributed  abundantly  in  the  wind. 
Closely  related  to  the  fireweeds  are  three  or  four  species  of 
willow-herbs  with  slender  capsules  packed  full  of  small  tufted 
seeds.  Here,  too,  should  be  classified  the  evening-primroses 
and  Ganras,  with  their  fuchsia-like  yellow  flowers.  Five  or  six 
varieties  of  evening-primroses  occur  in  different  parts  of  the 
state.  The  white  evening-primrose  is  limited  to  the  western 
portion.  The  shrubby  prairie  evening-primrose  is  common 
over  the  prairie  district.  The  most  abundant  is  the  ordinary 
evening-primrose  of  roadsides,  known  by  its  yellow  flowers, 
with  four  large  petals  and  calyx  growing  up  around  the  fruit- 
rudiment  and  adherent  to  it  The  Gauras  are  rare  herbs,  or 
half-shrubs,  not  abundant  except  in  the  southwestern  districts. 
They  may  be  known  by  the  fuchsia-like  flowers,  red  in  one 
species — the  scarlet  Gaura — and  pink  in  the  other.  The  flow- 
ers are  smaller  than  those  of  the  evening-primroses,  but  rather 
larger  than  those  of  the  willow-herbs. 

Enchanter's  nightshades.  Two  herbs  of  woodland  districts, 
known  as  enchanter's  nightshades,  are  grouped  in  the  evening- 
primrose  family.  They  are  low  herbs  with  the  habits  and 
appearance  of  shade  plants.  Their  leaves  are  opposite  and 
are  more  or  less  triangular.  The  small  white  fuchsia-like  flow- 
ers are  borne  in  loose  terminal  racemes,  and  the  capsules, 
when  they  mature,  are  covered  with  hooked  prickles.  The 
little  pear-shaped  burs  that  are  found  upon  one's  clothing  after 
an  autumnal  ramble  in  the  woods  will  probably  be  the  fruits 
of  the  enchanter's  nightshade.  The  two  varieties  of  nightshade 
may  be  distinguished  by  their  size,  one  of  them  varying  from 
a  foot  to  two  feet  in  height,  while  the  other  is  seldom  over  five 
inches  tall. 

Water-milfoils.  The  plants  known  as  water-milfoils  include 
five  or  six  Minnesota  species,  of  which  the  so-called  mare's  tail  or 
jointweed  is  the  most  striking  in  form.  It  is  a  slender,  erect, 
unbranched  plant,  found  growing  on  wet  mud  or  in  the  water. 


336  Minnesota  Plant  Life. 

and  has  a  stem  composed  of  joints  like  those  of  the  well-known 
scouring-rushes.  At  each  joint,  however,  is  a  whorl  of  from 
six  to  twelve  green,  lance-shaped  leaves.  The  plant  cannot, 
therefore,  be  mistaken  for  a  scouring-rush,  for  it  has  functional 
foliage  leaves.  Another  kind  of  water-milfoil  is  the  mermaid- 
weed,  with  two  sorts  of  leaves.  If  the  plant  has  grown  partly 
submerged,  the  leaves  below  the  surface  of  the  water  will  be 
like  feathers,  while  the  leaves  above  will  be  oval  and  only  slightly 
notched.  The  flowrers  are  borne  in  the  axils  of  the  leaves  above 
the  water  and  the  fruit  is  triangular  in  cross  section,  with  three 
deep  grooves.  The  true  milfoils  are  exceedingly  abundant  in 
the  lakes  and  ponds  of  Minnesota.  They  may  be  recognized 
by  their  jointed  pale-reddish  stems,  with  whorls  of  feather- 
shaped  leaves  each  with  fine  thread-like  dissected  lobes.  The 
flowers  are  borne  in  the  axils  of  small,  oval  leaves,  toward  the 
end  of  the  stem,  where  it  emerges  from  the  water.  The  flow- 
ering stem  protrudes  above  the  surface  like  the  spike  of  a  pond- 
weed.  No  pondweed,  however,  has  these  whorls  of  feather- 
shaped  leaves.  Three  or  four  different  varieties  of  water-mil- 
foils occur  within  the  state,  and  the  plants  need  not  be  confused. 
For  the  most  part  milfoils  prefer  deep  water  and  are  found  grow- 
ing along  with  pondweeds  outside  the  lily-pad  zone  and  on  bars 
or  sandy  bottoms. 

The  twenty  sixth  order  includes  three  families,  each  of  which 
is  represented  by  Minnesota  forms.  These  are  the  ginsengs, 
the  parsleys  and  the  dogwoods.  The  Minnesota  forms  of  the 
ginsengs  and  parsleys  are  all  herbs,  while  the  dogwoods  are  all 
of  them  shrubs — one,  the  dwarf  dogwood  or  cornel,  being  only 
three  or  four  inches  high.  The  others,  however,  are  shrubs 
of  good  size. 

Spikenards,  wild  sarsaparillas  and  ginsengs.  To  the  ginseng 
family  belong  five  Minnesota  species — the  spikenard,  the  wild 
sarsaparilla  and  wild  elder,  together  with  the  ginseng  or  "sang" 
and  the  dwarf  ginseng  or  groundnut.  The  first  three  are  char- 
acterized by  leaves  made  up  of  leaflets  arranged  as  in  the  ash, 
that  is,  the  leaflets  are  pinnately  grouped.  In  the  last  two  the 
leaflets  are  arranged  as  in  the  Virginia  creeper — that  is,  pal- 
mately  grouped.  The  spikenard  is  a  large  herb,  from  three  to 
six  feet  high,  with  thick,  sweet-scented  root.  The  leaflets,  ar- 


Minnesota  Plant  Life. 


337 


ranged  in  pinnate  groups,  are  developed  in  such  manner  as  to 
form  one  large  three-branched  leaf,  of  which  there  are  several 
upon  the  branching  stem.  The  flowers  are  arranged  in  the 
kinds  of  clusters  known  as  umbels,  characteristic  also  of  the 
parsley  family.  In  the  spikenard  the  umbels  are  massed  to- 
gether into  a  large  panicled  inflorescence.  The  fruits,  forming 
very  large  and  ornamental  bunches  when  ripe,  are  of  a  red- 
purple  color,  globular  in  shape  and  not  edible. 

The  wild  sarsaparilla  is  not  furnished  with  an  erect,  branch- 
ing stem,  but  the  leaves  and  flowering  axes  arise  from  a  long, 
underground  rootstock.  The  flowers  are  produced  at  the  apex 
of  the  flowering  axis  in  a 
group  consisting  usually  of 
three  umbels,  arranged  so  as 
to  form  a  flat-topped  cluster. 
The  fruit  is  purplish-black, 
nearly  spherical,  and  long- 
itudinally grooved.  The 
wild  elder  has  leaves  like 
those  of  the  elder  bush. 
The  umbels  are  numerous 
and  simple,  aggregated  to- 
gether in  groups  towards 
the  end  of  the  leafy,  erect 
stem,  and  the  fruits  are  dark 
purple,  five-grooved  when  FlG" 1( 

dry.     The  whole  plant  is  more  or  less  beset  with  slender  bristles. 
The  two  varieties  of  ginseng  may  be  distinguished  by  their 
leaves.     In  the  true  ginseng  the  leaves  are  made  up  of  five 
stalked  leaflets,  while  the  leaflets  in  the  dwarf  ginseng  are  ses- 
sile and  vary  from  three  to  five  in  number.     In  both  plants  the 
leaves  are  arranged  palmately,  and  in  each  there  is  a  swollen 
root — almost  globular  in  the  dwarf  ginseng,  and  ovoid-tuberous 
and  sometimes  branched  in  the  true  ginseng.     The  dwarf  gin- 
seng rarely  exceeds  six  inches  in  height,  but  the  true  ginseng 
may  reach  the  height  of  a  foot  and  a  half.     The  flowers  and 
fruits  are  arranged  in  small  umbels.     In  the  true  ginseng  the 
fruit  is  crimson,  while  in  the  dwarf  ginseng  it  is  yellow.     Gin- 
seng roots  are  commercially  valuable  on  account  of  the  use 
which  the  Chinese  make  of  the  plant  in  their  pharmacopoeia. 
23 


338 


Minnesota  Plant  Life. 


By  American  or  European  physicians  the  plant  is  not  consid- 
ered to  be  of  any  medical  value  whatever. 

The  parsley  family.  The  parsley  family  in  Minnesota  in- 
cludes about  thirty-five  species  of  herbs,  very  difficult  to  dis- 
criminate without  a  technical  examination  of  their  peculiari- 
ties. In  all  of  them  the  flowers  are  produced  in  compound 
or  simple  umbels,  with  the  exception  of  the  curious  button- 
snakeroot,  which  resembles  in  its  appearance  a  one  seed-leafed 
plant  much  more  than  it  does  the  other  members  of  the  pars- 
ley family.  In  this  the  leaves  are  parallel-veined  and  grass- 
like  and  the  flowers  are  clustered  in  heads.  Among  the  varie- 
ties of  parsley  found  in 
Minnesota  are  two  sorts 
of  pennyworts,  two  sorts 
of  black  snake-roots,  the 
cow-parsnip,  the  hog- 
fennel,  the  cowbane,  the 
w  a  t  e  r-h  e  m  1  o  c  k  ,  the 
meadow-parsnips  and  wa- 
ter-parsnips, the  hone- 
worts,  poison-hemlocks 
and  the  sweet  cicelys. 

The  plants  have  in  this 
family,  for  the  most  part, 
compound  leaves,  but  in 
a  few  species  the  leaves 
are  simple,  as  in  the  button-snakeroots,  the  introduced  hare's- 
ear,  the  Zizias,  and  the  pennyworts.  In  most  of  the  forms  the 
leaves  are  compounded  like  those  of  the  well-known  water- 
parsnips  or  wild  parsnips.  In  all  the  varieties  the  fruit  is  dry 
and  consists  of  two  carpels,  which  are  at  first  united  but  finally 
separate  from  each  other  along  their  faces,  so  as  to  produce  two 
half-fruits,  in  each  of  which  a  single  seed  is  inclosed.  There 
are  usually  oil-tubes  in  the  fruit,  so  that  the  odor  of  caraway 
seeds  is  a  peculiarity  of  most  of  the  fruits  in  the  family.  It  is 
upon  the  characters  of  the  mature  fruit  that  the  specific  descrip- 
tions are  based,  rather  than  upon  those  of  the  flower  or  of  the 
vegetative  tract ;  for  the  flowers,  and  to  some  extent  the  plant- 
bodies,  are  very  similar  throughout  great  numbers  of  species 
and  genera. 


FIG.  164.     Water-parsnip.    After  Britton  and  Brown. 


Minnesota  Plant  Life. 


In  the  sweet  cicelys  the  fruits  are  adapted  for  animal  distri- 
bution. They  are  elongated,  pointed,  armed  with  barbed  hairs 
and  grouped  in  very  loose  umbels.  These  are  common  plant, 
in  the  woods  throughout  the  state,  and  the  slender,  pointed 
seed,  which  attaches  itself  to  one's  clothing  during  a  forest 
ramble,  is  generally  the  half-fruit  of  one  or  the  other  species 
of  Minnesota  sweet  cicely.  The  snakeroots  form  little  bur- 


FIG.  165.     Wild  parsley.     After  photograph  by  Williams. 

• 

like  fruits  in  loose,  few-flowered  umbels.  These  are,  like  those 
of  the  sweet  cicelys,  intended  for  animal  distribution ;  but  most 
parsley  fruits  have  smooth  or  ribbed  surfaces  and  do  not  attach 
themselves  to  animals.  In  some  the  fruits  are  winged  to  a 
degree,  and  probably  obtain  distribution  through  the  agency 
of  the  wind.  The  roots  of  certain  plants  of  the  parsley  family 
are  very  poisonous,  and  to  children  eating  those  of  the  pois«m- 


340 


Minnesota  Plant  Life. 


hemlock  or  of  the  wild  parsnips  or  cowbane,  they  often  prove 
fatal.  To  the  parsley  family  belong  some  garden  vegetables, 
such  as  carrots  and  parsnips.  Here,  also,  are  the  plants  fur- 
nishing coriander  and  caraway  seeds.  The  perfume,  myrrh,  is 
obtained  from  a  European  variety. 

Dogwoods.  There  are  eight  varieties  of  dogwood  in  Min- 
nesota, all  of  them  rather  closely  related.  In  dogwoods  the 

flowers  are  rather  incon- 
spicuous and  borne  in  heads, 
to  be  regarded  as  compact 
umbels.  In  some  of  the 
varieties  about  four  large 
white,  petal-like  leaves  are 
produced  just  below  the 
head  of  flowers,  so  that,  as 
in  the  sunflower  family,  the 
whole  head  resembles  a 
single  flower.  Two  Minne- 
sota species  have  these 
handsome  white  leaves  be- 
low the  flower  heads.  One, 
the  dwarf  cornel,  or  bunch- 
berry,  is  a  little  shrub  from 
two  to  eight  inches  in 
height,  with  the  upper  part 
of  the  stem  herbaceous. 
The  above-ground  branch, 
which  is  generally  simple, 
arises  from  a  prostrate,  slender  rootstock.  The  leaves  are  ovate, 
with  several  strong  longitudinal  ribs,  and  are  clustered  in  a 
whorl  below  the  pedicel  of  the  flower-head.  In  fruit  the  dwarf 
cornel  produces  from  each  flower  a  little  ovoid  or  spherical 
stone-fruit  of  a  scarlet  color.  The  fruits  are  aggregated  in 
heads  as  the  flowers  were,  and  form  characteristic  red  bunches, 
giving  occasion  to  one  of  the  common  names. 

The  other  dogwood,  in  which  conspicuous,  white  petal-like 
leaves  are  clustered  below  the  flowering  head,  has  these  leaves 
very  large,  an  inch  or  more  in  length,  strongly  notched  at  the 
tip.  Sometimes  in  this  variety,  known  as  the  flowering  dog- 


FIG.  166.     Water-hemlock.     After  Chesnut. 
F.  B.  86,  U.  S.  Dept.  Ag. 


Minnesota  Plant  Life. 


34i 


wood,  the  petal-like  leaves  are  pinkish,  but  more  commonly 
they  are  white.     The  bush  occurs  rather  sparingly  along  the 
Mississippi  river,  from  Stearns  county  to  the  Iowa  line.     Its 
fruits  are  very  similar  to  those  of  the  dwarf  cornel  but  are  a 
little  more  elongated.     They  have  the  same  scarlet  color  ami 
cherry-like  structure.     In  the  rest  of  the  Minnesota  dogwoods, 
including  the  shrubs  known  as  red  osiers  and  kinnikinics,  the 
flowers  are  larger  and  looser,  cymose  or  paniculate,  and  not  pro- 
vided with  the  large,  petal-like  bracts  beneath.     The  shrubs  are 
distinguished  from  each  other  by  their  foliage,  the  shape  of  their 
flower  clusters,  the  color  of  their  twigs  and  the  stones  of  their 
fruits.     The  round-leafed  dog- 
wood, very  abundant  through- 
out the  state,  is  a  bush  from 
three    to   ten    feet   in   height, 
much  branched  and  furnished 
with  broadly  ovate,  entire-mar- 
gined leaves.     The  fruit  is  of  a 
light  blue  color  and  has  an  al- 
most globular  stone.     Closely 
related    to    the    round-leafed 
dogwood  is  the  silky  cornel  or 
kinnikinic,  distinguished  by  its 
silky-haired  twigs,  quite  differ- 
ent  from   the   green,    smooth 
twigs  of  the  round-leafed  dog- 
wood.   The  fruit  is  of  the  same 
light  blue  color,  but  the  leaves 
are  somewhat  slender,  approaching  in  their  shape  ordinary  plum 
leaves.     The  rough-leafed  dogwood  grows  a  little  larger  than 
either  of  its  relatives  which  have  been  mentioned  and  may  be 
recognized  by  the  reddish-brown,  hairy  twigs,  the  rough,  hairy 
upper  surfaces  of  the  leaves  and  the  spherical,  white  fruits,  in 
which  the  stone  is  but  slightly  furrowed  and  not  much  flattened. 
Bailey's  dogwood  is  very  similar  in  appearance,  but  has  rather 
narrower  lance-shaped    leaves  and  white  fruits,  in  which    the 
stone  is  flattened  and  furrowed  along  the  edge.     The  red  osier 
or  kinnikinic  is  one  of  the  most  frequent  varieties  through  the 
northern  and  central  portions  of  the  state.     It  is  a  shrub  from 
three  to  fifteen  feet  in  height,  with  bright  red  or  purple.  >mooth 


FIG.  167.    Dwarf  cornel.    After  Britton  and 
Brown. 


342  Minnesota  Plant  Life. 

twigs,  sometimes  slightly  hairy  towards  the  tips.  The  leaves 
are  broadly  ovate  and  the  fruits  are  white,  with  stones  of  a 
generally  globose  shape.  This  variety,  together  with  the  silky 
cornel,  is  utilized  by  the  Indians — under  their  name  of  kinniki- 
nic — as  an  adulterant  of  tobacco.  The  inner  bark  of  the  twigs 
is  collected  and  dried,  mixed  with  the  tobacco  and  believed  by 
the  Indians  to  improve  its  flavor.  It  should  be  mentioned  that 
the  Indians  apply  the  same  name  to  other  materials  which  they 
use  in  a  similar  manner,  as  for  example,  sumac  leaves.  The  name 
of  the  Redwood  river  is  said  to  be  derived  from  the  red  osier. 

The  panicled  dogwood  is,  perhaps,  the  most  abundant  species 
in  the  southern  and  through  the  central  portions  of  the  state. 
It  is,  like  its  relatives,  a  branched  shrub,  and  has  smooth,  gray 
twigs.  The  leaves  are  lance-shaped,  with  slender  tips.  The 
fruits  are  white  in  color  and  have  slightly  furrowed  stones. 

All  the  dogwoods  which  have  been  described  are  character- 
ized by  opposite  leaves.  One  other  kind,  the  alternate-leafed 
cornel,  is  not  uncommon  in  Minnesota,  except  in  the  region 
of  the  international  boundary.  As  its  name  indicates,  the  leaves 
are  alternate.  The  fruit  is  of  a  blue  color  and  has  a  channeled 
stone.  In  the  southern  portions  of  its  range  this  variety  some- 
times becomes  a  small  tree,  but  in  Minnesota  it  remains  of 
shrubby  habit.  The  wood  is  heavy,  close-grained  and  of  a 
reddish-brown  color. 

Most  of  these  varieties  of  dogwood  grow  best  in  damp  woods 
or  thickets  and  along  the  shores  of  lakes.  The  dwarf  cornel, 
however,  is  by  preference  an  inhabitant  of  tamarack  swamps, 
where  it  is  found  along  with  wintergreens  and  lady's-slippers. 
It  is  abundant,  too,  in  the  pine  woods,  particularly  in  shaded 
places.  The  dogwoods  are  exceedingly  beautiful  shrubs  when 
disposed  along  broad  lake  beaches,  where  they  select  the  back- 
strand  or  mid-strand  and  often  form  handsome  hemispherical 
plant-bodies  ten  feet  or  more  in  height  and  fifteen  feet  in 
breadth,  growing  regularly  and  looking  as  if  they  had  been 
trimmed  by  some  careful  gardener.  Together  with  certain  va- 
rieties of  willows  which  have  the  same  habit  of  growth,  they  are 
among  the  most  noticeable  plants  of  level  lake  shores,  especially 
in  the  northern  part  of  the  state.  They  abound,  too,  around 
meadows  and  in  the  edges  of  woods  or  along  streams. 


Chapter  XXXIV. 

High  Types  and  Low  Types  of  Flowers. 


There  have  now  been  passed  in  review  the  twenty-six  orders 
of  two  seed-leafed  plants  which  agree  in  showing  no  fusions  of 
the  petals  of  the  flower  into  corolla  tubes.  Indeed,  some  of 
them  have  no  petals.  But  in  such  forms  as  produce  flowers 
with  petals,  the  typical  honeysuckle  tube  or  morning-glory 
funnel  is  not  developed.  A  number  of  differences  in  flowers 
and  fruits  have  been  recorded,  and  it  may  not  be  amiss,  before 
passing  to  the  consideration  of  succeeding  orders,  to  note  briefly 
the  general  law  under  which  flowers  vary  from  lower  types  to 
higher.  There  is  a  distinction,  pretty  clear  in  the  mind  of  the 
botanist,  between  lower  or  simpler  sorts  of  flowers  and  higher 
or  more  complex  kinds.  The  distinction  does  not,  however, 
consist  in  showiness,  size,  color,  perfume  or  abundance.  Con- 
sidered botanically,  some  large  and  beautiful  blossoms  are  lower 
in  type  than  other  tiny,  inconspicuous  flowers  that  might  almost 
escape  the  observation  of  the  amateur. 

In  order  to  understand  the  distinctions  which  have  weight 
with  botanists  it  is  necessary  to  remember  from  what  sort  of 
structures  flowers  are  believed  to  have  developed.  A  proto- 
type of  all  flowers  is  the  pine  cone — an  aggregate-body  is  fore- 
shadowed even  among  flowerless  plants,  notably  by  the  club- 
moss  cones.  It  will  be  recollected  that  in  club-mosses  the 
ends  of  many  of  the  stems  gathered  their  leaves  more  closely 
together  than  elsewhere,  and  on  the  upper  side  of  each  of  such 
leaves  was  placed  a  little  spore-containing  sac.  The  cone  of 
the  club-moss  is  an  axis  upon  which  spore-bearing  leaves  are 
distributed.  As  has  already  been  suggested,  in  the  discussion 
of  the  club-mosses,  the  primitive  type  of  spore-bearing  leaf  had 
also,  as  part  of  its  duty  in  the  plant  economy,  the  starch-making 
work  of  an  ordinary  leaf.  But  by  a  division  of  labor,  some 


244  Minnesota  Plant  Life. 

leaves,  especially  toward  the  tips  of  branches — therefore  raised 
higher  from  the  ground — devoted  themselves  particularly  to 
spore-manufacture,  leaving  the  starch-making  to  lower  leaves 
on  the  stem.  Naturally  it  was  more  important  for  the  plant 
to  use,  for  spore-production,  those  leaves  farthest  from  the 
ground,  because  if  produced  at  a  height  the  spores  could  be 
distributed  over  a  wider  area. 

When  the  habit  of  making  two  kinds  of  spores  became  fixed 
among  the  distant  ancestors  of  modern  seed-bearing  plants,  the 
clusters  of  spore-bearing  leaves  or  cones  came,  in  the  pines  and 
their  allies,  to  be  specialized,  so  that  one  cone  devoted  itself 
to  the  manufacture  of  the  small-spores  while  another  produced 
only  large-spores  in  the  little  cases  on  its  leaves.  Thus  there 
originated  the  very  different  pollen-bearing  and  seed-bearing 
cones,  which  may  be  observed  in  such  plants  as  the  white  pine, 
tamaracks  and  junipers.  Probably,  however,  in  some  varieties 
there  was  not  this  separation,  upon  their  special  axes,  of  the 
two  sorts  of  leaves;  but  one  sort  arose  toward  the  tip  of  the 
axis,  while  the  other  appeared  lower  down,  so  that  mixed  cones, 
with  carpels  or  large-spore-bearing  leaves  toward  the  tip,  and 
stamens  or  small-spore-bearing  leaves  toward  the  base  of  the 
axis,  originated.  After  the  seed-habit  had  become  fixed,  it 
is  apparent  that  the  same  advantage  which  club-mosses  de- 
rived from  having  their  spore-producing  leaves  highest  on  the 
stem,  would  now  be  derived  from  having  the  seed-rudiment- 
producing  leaves,  or  carpels,  highest  on  the  stem.  The  advan- 
tage of  height  above  the  substratum  which  was  manifest  in  the 
distribution  of  spores  would  be  retained  as  favorable  to  the  dis- 
tribution of  seeds.  The  primitive  higher  flowering  plants  no 
doubt  had  their  seeds  distributed  by  the  wind,  and  it  was, 
therefore,  important,  from  the  plant's  point  of  view,  that  the 
carpels  should  stand  higher  in  the  flower  than  the  stamens. 
This  will  account  for  the  central  position  of  the  pistil  and  the 
peripheral  position  of  the  stamens. 

The  crowding  together  of  the  leaves  of  the  flower,  which 
became  possible  when  they  abandoned  their  starch-making 
functions,  may  be  seen  foreshadowed  even  in  the  cones  of  the 
club-mosses.  It  becomes  still  more  marked  in  the  pines,  while 
in  flowering-plants  the  great  majority  have  the  cone  or  flower- 


Minnesota  Plant  Life.  ~*c 

axis  so  short  that  it  is  actually  flat  or  even  depressed  in  the 
centre,  as  in  roses.  To  this  rule,  however,  there  are  a  number 
of  important  exceptions,  as  for  example,  the  little  mousetail, 
a  member  of  the  crowfoot  family,  with  its  elongated  axis,  upon 
which  the  nutlets  are  produced.  The  anemones,  also,  and 
some  of  the  rose  family,  like  the  strawberry,  have  conical  or 
cylindrical  floral  axes  upon  which  the  carpels  are  distributed. 
These  elongated  axes  may  not,  indeed,  in  such  instances,  be 
really  primitive,  but  may  rather  be  secondarily  adaptive.  Yet 
the  highest  types  of  flowers  do  not  have  such  long  axes,  but  are 
flat,  with  the  carpels  central  and  the  stamens  in  encircling  rings. 
If,  now,  one  can  imagine  a  pine  cone,  the  tip  of  which  is  com- 
posed of  seed-bearing  scales,  while  at  the  base  are  disposed  the 
pollen-scales  or  stamens,  and  then  imagine  further  that  the  tip 
of  this  axis  is  pressed  down  with  the  thumb  until  the  whole 
becomes  flat  and  saucer-like,  it  is  apparent  that  the  seed-bearing 
scales  will  now  be  at  the  centre,  while  the  pollen-bearing  scales 
will  form  a  ring  around  the  outside  of  the  saucer.  Precisely 
such  change  in  shape  of  the  ancestral  cone  is  believed  to  have 
taken  place  in  the  plant  world  under  the  slow  workings  of 
structural  improvements  through  the  ages.  Many  advantages 
in  flowers  might  be  derived  by  the  passage  from  the  elongated 
to  the  flattened  type  of  axis.  If,  for  example,  the  flower  came 
to  depend  for  pollination  upon  insects,  the  flattening  of  the  axis 
might  make  the  work  of  the  insects  surer,  or  if  the  flower 
depended  upon  its  own  pollen  for  pollination,  the  bringing  of 
the  stamens  and  the  stigmas  into  the  same  plane  would,  per- 
haps, facilitate  the  process.  Of  course  the  ancient  prototypes 
of  flowers  could  not  be  expected  to  have  these  flattened  axes, 
because  in  them  the  division  of  labor  between  spore-producing 
and  starch-making  leaves  had  not  arisen,  and  each  leaf  on  the 
axis  had  to  stand  in  such  a  position  that  it  could  get  light  for 
itself  from  the  sun  without  shading  too  much  the  other  leaves 
near  by.  Elongated  flower-axes,  like  those  of  the  pines,  remind 
one  of  earlier  days,  in  which  such  axes  had,  in  addition  to  their 
production  of  spores, also  a  starch-making  work  to  perform.  Any 
flower  which  retains  in  its  structure  the  marks  of  earlier,  less 
improved  conditions,  is  conceived  in  this  respect  to  be  of  lower 
type  than  one  which  has  lost  these  marks,  and  this  is  the  true 


Minnesota  Plant  Life. 

criterion  of  rank  among  flowers.  Precisely  the  same  thing  is 
apparent  in  human  society,  for  a  civilized  man  who  retains  char- 
acteristics which  may  have  been  valuable  to  the  savage  but  have 
been  outgrown  during  the  progress  of  civilization,  is  regarded 
as  of  lower  grade  than  his  fellows. 

The  flattening  of  the  axis  of  the  flower  into  a  disk  is  pos- 
sibly the  most  fundamental  evidence  of  improvement;  that  is, 
of  passage  from  a  lower  to  a  higher  type.  Connected  with 
this  flattening  arose  a  rearrangement  of  the  parts  of  the  flower. 
In  the  pine  cone  the  scales  are  arranged  spirally,  just  as  if  they 
were  foliage  leaves,  but  in  apples  the  stamens  and  carpels  are 
produced  in  whorls.  A  spiral  arrangement  of  stamens  and 
carpels,  because  it  is  more  like  the  fundamental  grouping  of 
foliage  leaves  upon  a  stem,  is  believed  to  indicate  a  lower  type 
of  flower  than  when  whorls  are  substituted — a  grouping  not 
so  common  among  foliage  leaves,  but  quite  unobjectionable  for 
spore-producing  leaves.  Even  among  the  pines  the  tendency 
to  gather  the  leaves  of  the  flower  into  more  compact  clusters 
may  be  seen  in  such  plants  as  the  junipers  and  red  cedars. 

Again,  as  flowers  came  to  be  blocked  out  as  definite  spore- 
producing  tracts,  made  up  of  leaves  arranged  on  a  shortened 
axis,  the  leaves  below  the  stamens  became  modified  from  their 
proximity  to  the  true  floral  parts.  Thus  the  area  known  as 
perianth  came  into  existence.  By  a  further  specialization  peri- 
anth came  to  consist  of  outer  perianth — that  is,  lower  perianth, 
or  calyx,  and  inner — that  is,  upper  perianth,  or  corolla.  Under 
such  conditions  what  may  be  known  as  a  typical  flower  ap- 
peared, and  such  a  typical  flower  may  be  described  as  an  axis, 
bearing  essential  leaves,  viz.,  carpels  and  stamens,  surrounded 
by  the  accessory  leaves  of  the  calyx  and  corolla. 

In  all  the  four  regions  of  the  typical  flower  modifications 
and  improvements  are  possible.  The  carpels,  for  example,  may 
blend  together  into  a  single  fruit-rudiment  or  pistil.  Thus  the 
fruit  of  the  lily  is  regarded  as  made  up  of  three  carpels  blended 
together.  Such  a  blending  would  be  regarded  as  an  improve- 
ment over  the  separate  condition  of  the  scales  in  the  cones  of 
the  pine.  It  is  certainly  farther  removed  from  that  primitive 
arrangement  in  which,  on  account  of  their  starch-making  duties, 
the  leaves  were  necessarily  separate.  After  having  thus  be- 


Minnesota  Plant  Life. 

come  blended,  conditions  might  arise,  when,  by  the  deep  groov- 
ing of  the  pistil,  the  carpels  would  again  be  separated  and  such 
'a  secondary  separation  won1-1,  mark  a  higher  type  than  the  orig- 
inal blended  condition.  It  is  sometimes  difficult  to  tell  whether 
a  separation  of  the  carpels  is  primitive  or  secondary.  In  the 
region  of  the  stamens  the  separate  leaves  indicate  a  primitive 
type,  while  the  blending  of  the  stamens  into  a  tube,  as  in  the 
mallows,  is  regarded  as  an  improvement,  and  consequently  indi- 
cates a  higher  type.  Likewise  the  blending  of  the  parts  of  the 
calyx  into  a  tube  .is  regarded  as  a  modification  of  that  original 
condition  in  which  the  calyx  leaves  were  separate. 

Not  only  may  parts  of  the  same  group  blend  with  each  other, 
but  they  may  also  blend  with  the  group  next  to  them.  Thus  the 
production,  in  orchid  flowers,  of  stamens  apparently  springing 
from  the  surface  of  the  pistil  is  regarded  as  evidence  of  the 
blending  together  into  one  body  of  what  were  originally  sepa- 
rate stamens  and  pistils.  For  this  reason  the  orchid  flower,  in 
which  such  a  condition  has  arisen,  is  regarded  as  higher  in  type 
than  the  lily  flower,  for  in  the  latter  the  blending  of  stamens 
and  pistil  has  not  been  effected.  A  great  many  such  blend- 
ings  exist.  Sometimes  the  stamens  are  produced  upon  the 
petals  or  upon  the  calyx  leaves.  Sometimes  both  the  petals 
and  stamens  seem  to  arise  from  the  calyx,  indicating  a  fusion 
into  one  body  of  all  three  regions  of  the  flower — a  condition 
evidently  remote  from  the  primitive  type,  and,  therefore,  indica- 
tive of  higher  rank.  Especially  is  the  blending  of  the  calyx 
with  the  surface  of  the  pistil  regarded  as  an  improvement  over 
the  condition  in  which  these  two  areas  are  quite  distinct.  Apple 
flowers,  for  example,  develop  petals  and  stamens  upon  the 
calyx  and  the  latter  is  blended  with  the  surface  of  the  carpels, 
giving  an  additional  protective  layer  to  the  seeds  and  permit- 
ting the  important  function  of  assisting  in  seed-distribution  to 
be  borne  by  a  part  of  the  flower  below  the  essential  organs. 
In  willow-herbs,  too,  or  fireweeds,  the  calyx  is  blended  with 
the  pistil,  and  when  the  capsule  is  mature  it  consists  of  two 
protective  layers  around  the  seeds  instead  of  one.  All  these 
blendings  of  parts  indicate  higher  rank. 

Another  way  in  which  flowers  become  modified  from  prim- 
itive forms  is  by  the  development  of  differences  between  the 


348  Minnesota  Plant  Life. 

parts  of  the  same  area.  The  violet  flower,  with  one  of  its  petals 
spurred,  is  conceived  to  be  higher  in  rank  than  the  linden  flower, 
in  which  all  the  petals  are  alike.  Irregularity  of  the  flower 
marks  some  improvement  over  regularity,  and  it  should  always 
be  remembered  that  the  irregular  flower  is  irregular  for  a  pur- 
pose. The  irregularity  may  be,  and  usually  is,  an  adaptation 
to  the  habits  of  the  insects  which  effect  pollination.  There- 
fore, the  strongly  irregular  flowers  of  orchids,  beautifully 
adapted  to  the  sizes,  shapes,  weights  and  feeding-habits  of  bees 
or  moths,  are  improvements  over  the  regular  flowers  of  tulips, 
blue  flags  and  trilliums.  Irregularity  may  arise  in  a  variety 
of  ways.  A  very  common  type  is  two-sidedness  of  the  flower  and 
the  substitution  of  the  two-sided  symmetry  for  the  radial  sym- 
metry. Just  as  man,  whose  body  can  be  divided  into  approxi- 
mately equal  halves  by  only  one  plane,  is  on  this  account  a 
higher  structural  type  than  the  starfish,  the  body  of  which  may 
be  divided  into  several  approximately  equal  portions  by  planes 
radially  disposed,  so  the  two-sided  flower  of  an  orchid,  or  that 
of  the  pea  or  larkspur,  must  be  regarded  as  structurally  higher 
than  related  radially-symmetrical  forms,  such  as  lilies,  acacias, 
lindens  or  buttercups. 

Along  with  the  development  of  upper-  and  under-sidedness 
in  the  flower  go  a  number  of  changes  in  the  shapes,  positions, 
numbers  and  sizes  of  the  floral  organs.  Thus  in  the  pea  flower, 
one  petal  is  larger  than  the  others,  and  forms  the  so-called 
standard.  The  other  four  petals,  grouped  in  pairs,  constitute 
the  so-called  wings  and  keel  of  the  flower.  The  stamens  are 
blended  together  into  a  tube,  but  one  stamen  in  the  plane  of 
symmetry  stands  distinct  from  the  rest.  The  carpels,  too,  in 
the  pea  flower  become  reduced  in  number  and  the  pod  is  often 
flattened  in  the  plane  of  the  symmetry. 

There  should  be  no  difficulty  in  comprehending  how  a  flower 
that  manifests  in  its  whole  structure  a  great  departure  from 
the  primitive  type  should  be  considered  as  higher  than  a  flower 
that  approximates  in  its  structure  more  closely  to  the  early 
conditions.  It  must  be  observed,  moreover,  that  the  different 
orders  of  flowering  plants  do  not  constitute  a  single  series  of 
advancement.  One  order  may  show  improvement  along  one 
path,  while  another  shows  improvement  in  quite  a  different 


Minnesota  Plant  Life.  349 

direction.  In  the  same  order  the  lower  families  may  have  reg- 
ular flowers,  while  the  flowers  of  the  higher  families  have 
acquired  more  specialized  irregular  shapes.  The  proper  ar- 
rangement of  the  orders  is  not  one  of  sequence,  but  rather  the 
kind  of  arrangement  that  is  seen  in  genealogical  charts,  or  in 
the  trunks,  main  branches,  secondary  branches  and  twigs  of  a 
tree.  Grasses  and  sedges,  for  example,  represent  the  perfection 
of  certain  lines  of  development.  Orchids  represent  the  per- 
fection of  another  line  of  improvement,  and  dogwoods  occupy 
relatively  another  terminal  position.  Yet  it  is  possible  in  a 
general  way  to  regard  the  plant  with  two-leafed  seedlings  as 
showing  a  higher  type  of  embryo-structure  than  the  plant  with 
one-leafed  seedlings,  and  when  the  orders  of  plants  are  discussed 
in  sequence,  the  former  group  is  considered,  as  a  whole,  subse- 
quent to  the  latter.  On  this  account,  however,  it  should  not 
be  supposed  that  willow  flowers  are  of  higher  structural  type 
than  orchid  flowers,  for  orchids  are  among  the  most  perfected 
of  plants  with  the  lower  type  of  embryo,  while  willows  are 
among  the  least  perfected  types  with  the  higher  kind  of  embryo. 
In  general,  that  higher  class  in  which  the  petals  are  blended  into 
corolla  tubes  marks,  in  this  respect,  an  advance  over  those  plants 
in  which  such  blending  does  not  exist.  But  it  would  be  a 
mistake  to  suppose  that  the  flower  of  the  cranberry  is  struc- 
turally more  complicated  than  the  pea  or  the  violet  flower. 
As  in  the  case  of  the  willows  and  the  orchids  just  compared, 
the  cranberry  belongs  to  one  of  the  lowest  orders  of  corolla- 
tube-producing  plants,  while  the  peas  and  violets  are  relatively 
high  types  of  the  generally  lower  series,  in  which  no  corolla 
tubes  are  formed. 

With  this  explanation  of  a  somewhat  difficult  point — look- 
ing toward  an  answer  to  the  question,  why  is  one  flower  con- 
sidered of  higher  type  than  another? — there  may  now  be  dis- 
cussed the  eight  remaining  orders  of  two-seed-leafed  plants 
in  which  corolla  tubes  rather  than  separate  petals  are  almost 
universally  the  rule. 


Chapter  XXXV. 

From  Wintergreens  to  Choffweeds. 


The  twenty-seventh  order  includes  six  families,  two  of  which, 
the  wintergreens  and  the  heaths,  are  represented  in  Minnesota. 
About  twenty  two  species  of  heaths  are  native  to  the  state. 
Here  are  classified  the  huckleberries,  cranberries,  blueberries, 
snowberries,  bearberries,  trailing  arbutuses,  checkerberries, 
leatherleafs,  Cassiopes,  rosemarys,  laurels,  Menziesias,  and  Lab- 
rador teas.  To  this  family  belong  also  the  azalias,  rhododen- 
drons and  heathers. 

Wintergreens.  The  wintergreen  family  in  Minnesota  com- 
prises nine  or  ten  species  of  true  wintergreens;  the  one-flow- 
ered wintergreen,  two  pipsissewas  or  spotted  wintergreens,  the 
pine-drops,  the  Indian-pipe  or  corpse-plant,  and  the  pine-sap 
or  false  beechdrops.  The  last  three  plants  named  do  not 
exhibit  leaf-green  but  absorb  their  food  from  the  humus  of  the 
forest  floor,  taking  up  organic  substances  and  manufacturing 
no  starch  of  their  own.  The  others  are  green  plants  with 
somewhat  the  appearance  of  the  heaths,  except  that  they  are 
not  so  shrubby.  The  wintergreens,  from  branched  under- 
ground rootstocks,  produce  upright  stems  usually  less  than  a 
foot  in  height.  The  flowers  are  commonly  grouped  in  a  single 
slim  terminal  raceme,  each  flower  nodding  or  erect  in  the 
axil  of  a  small  bract  or  scale.  In  some  of  the  varieties  the  flow- 
ers have  the  stigmas  and  stigma-stalks  bent  down,  while  in 
others  the  stigma  projects  in  the  centre  of  the  flower. 

The  round-leafed  wintergreen,  very  abundant  in  pine  woods, 
throughout  the  northern  part  of  the  state,  has  rounded  or 
broadly  oval  leaves,  of  a  leathery  texture,  shining  and  ever- 
green, and  spreading  out  at  the  base  of  the  straight,  tall  flower- 
bearing  axis.  The  flowers  are  white,  rather  large  and  sweet- 
scented  and  are  arranged,  eight  or  ten  together,  in  their  ra- 


Minnesota  Plant  Life.  35I 

cemes.  The  green-flowered  strongly  resembles  the  round- 
leafed  wintergreen,  except  that  the  leaves  are  of  a  dull  green 
color  above  and  the  flowers  are  greenish-white  with  slight 
fragrance.  The  shinleaf,  unlike  the  two  preceding  species, 
has  papery  rather  than  leathery  leaves,  and  these  are  broad 
and  rounded  with  blades  rather  longer  than  their  stems.  The 
flowers  in  this  variety  are  greenish-white  and  very  sweet- 
scented.  The  bog  wintergreen,  found  in  cold  peat-bogs,  has 
the  leaves  of  the  green-flowered  wintergreen — that  is  to  say, 
they  are  broadly  oval,  leathery  and  of  a  dull  green.  The  flow- 
ers, however,  are  purple,  thus  easily  distinguishing 
this  variety.  The  pink-flowered  or  heart-leafed 
wintergreen  is  very  similar  to  the  bog  wintergreen, 
but  may  be  recognized  by  the  heart-shaped  bases 
of  the  leaves.  The  flowers  are  rose-pink  or  some- 
times purple. 

All  the  wintergreens  mentioned  have  the  stigma 
depressed  towards  the  under  side  of  the  flower. 
The  remaining  varieties  have  central  stig- 
mas.    The    lesser    wintergreen    resembles 
in  most  of  its  characters  the  green-flow- 
ered, but  has  the  thin  leaves  of  the  shin- 
leaf    wintergreen.     The   stamens   do   not, 
as  in  the  previous  varieties,  diverge  from 
the  fruit-rudiment,  but  close  around  it  in 
the  open  flower.     The  serrate-leafed  win-  Fic.ies.  wintergreen  plant 

n  in  flower.    After  Atkin- 

tergreen  has  flowers  very  much  like  those       son. 

of  the  lesser  wintergreen,   but  the  leaves 

are   almost   plum-leaf  shape  with   teeth  along  the   margin. 

Besides  the  forms  already  noted,  there  are  two  others  that 
are  but  slightly  different  from  the  typical  varieties.  The  round- 
leafed  wintergreen  sometimes  produces  leaves  red-veined  or 
red  instead  of  shining  green,  and  in  this  form  it  is  known  as 
the  red-leafed  wintergreen.  The  serrated  wintergreen,  which 
is  usually  from  four  to  ten  inches  in  height,  with  a  number 
of  flowers  in  a  one-sided  raceme,  may  exist  as  a  low  plant, 
less  than  four  inches  high,  with  from  three  to  eight  flowers 
and  rounded  leaves.  It  is  then  known  as  the  low  serrated 
wintergreen.  The  leaves  of  all  the  species  are  rather  pleasant 


352  Minnesota  Plant  Life. 

to  the  taste.  The  fruits  they  mature  are  five-grooved  spherical 
capsules  which  split  into  five  sections  to  release  the  small 
seeds. 

The  one-flowered  wintergreen  has  the  same  evergreen  leaves 
that  characterize  the  ordinary  varieties,  but  is  peculiar  for  the 
production  at  the  end  of  a  slender  axis  of  a  single,  rather  large, 
drooping,  white  or  pink  flower,  about  six  inches  or  less  in 
height.  The  leaves  are  almost  round,  with  short  stems,  and 
are  gathered  in  tufts  at  the  base  of  the  flowering  axis.  This 
variety  of  wintergreen  is  limited  to  the  northern  portion  of  the 
state,  where  it  occurs  among  the  moss  in  deep  balsam,  spruce 
or  tamarack  woods. 

Pipsissewas.  The  two  kinds  of  wintergreen  known  as  pip- 
sissewas  or  spotted  wintergreens,  if  they  are  found  in  fruit  can 
be  distinguished  at  once  from  the  preceding  forms.  In  the 
other  wintergreens,  when  the  capsules  open,  the  clefts  are  woolly 
at  their  edges,  but  in  the  pipsissewas  the  clefts  in  the  capsules 
are  not  at  all  woolly.  The  rarer  variety  of  spotted  wintergreen 
may  also  be  known  by  its  more  willow-shaped  leaves  with 
remote  notches  in  the  margins  and  by  the  disposition  of  the 
white  or  pinkish  flowers  in  cymes  rather  than  in  racemes.  The 
leaves  in  this  variety  are  spotted  with  white  along  the  veins, 
but  the  commoner  pipsissewa  has  bright,  shining  leaves  without 
spots,  considerably  shorter  and  broader  than  those  of  the  rarer 
kind.  The  flowers  are  clustered  four  or  five  in  a  group,  in  a 
somewhat  flat-topped  inflorescence  at  the  tip  of  their  axis. 
Both  of  these  plants  prefer  drier  woods  and  are  sometimes  abun- 
dant under  the  pines.  They  appear  also  in  hardwood  timber, 
but  rather  more  sparingly. 

Pine-drops.  The  pine-drops  is  a  rare  herb  of  the  northern 
part  of  the  state.  It  forms  an  upright,  unbranched  slender  stem 
from  six  inches  to  three  or  four  feet  in  length.  This  stem  is 
of  a  reddish  or  brown  color,  with  a  few  scaly  leaves  which  are 
not  green,  since  they  make  no  starch.  At  the  end  of  the  stem 
are  numerous,  nodding,  bell-shaped  white  flowers,  each  arising 
in  the  axil  of  a  little  scale.  Each  seed  has  a  small  thin  wing 
on  the  end.  The  root  area  is  unusually  small. 

Indian-pipes.  The  Indian-pipe,  otherwise  called  the  corpse- 
plant,  is  of  very  striking  appearance.  Several  stems  usually 


Minnesota  Plant  Life. 

353 

grow  together  in  a  tuft,  and  the  whole  plant-body  is  commonly 
of  a  snow-white  color,  with  yellowish  or  reddish  scales.  At  the 
tip  of  each  stem  is  a  single,  nodding  flower,  around  which  the 
bracts  are  white.  This  variety  is  not  uncommon  throughout 
the  state  and  is  to  be  looked  for  in  deep  woods  where  a  rich 
layer  of  decaying  leaves  has  collected. 

Pine-saps.  The  pine-sap,  more  abundant  in  the  pine  woods 
and  extending  south  to  Gull  lake  and  Taylor's  Falls,  resembles 
the  Indian-pipe  or  corpse-plant  in  almost  all  particulars,  but  it 
may  at  once  be  identified  by  its  having  several  flowers  clustered 
at  the  tip  of  each  stem,  instead  of  the  single  flower  of  the  more 
common  variety. 

The  three  plants  last  mentioned  are  quite  fungus-like  in  their 
habits  of  food-collection.  Unlike  most  flowering  plants,  they 
do  not  produce  leaf-green.  They  may  be  described  as  plants 
which  have  lost  the  power  of  making  their  own  starch,  and 
have  learned,  through  the  cooperation  of  root-fungi,  to  take 
their  food  in  complex  form  from  the  decaying  remains  of  other 
vegetation.  Structurally  they  are  not  very  different  from  the 
wintergreens,  and  so  must  be  classed  with  them  rather  than 
with  the  fungi,  which  physiologically  they  resemble.  Winter- 
greens  are  not  the  only  kind  of  flowering  plants  that  have 
given  rise  to  such  types  of  fungus-like  forms.  Among  the 
orchids  it  will  be  remembered  that  the  coralroots  showed  the 
same  tendency  to  take  their  food  "ready-made"  rather  than  to 
manufacture  it  independently  from  carbonic-acid  gas  and  water. 

Labrador  teas.  An  abundant  variety  of  Minnesota  heath 
growing  in  bogs,  especially  through  the  northern  part  of  the 
state,  is  the  Labrador  tea.  It  is  an  evergreen  shrub  with  leaves 
shaped  very  much  like  those  of  the  willow,  green  upon  the  upper 
side  and  covered  with  a  soft,  rust-brown  wool  below.  The 
margins  of  the  leaves  are  somewhat  curled  over  toward  the 
under  side.  The  flowers,  borne  in  umbels,  are  white,  and  each 
matures  a  five-chambered,  oblong  dry  capsule,  that  splits  from 
the  base  into  five  segments.  The  plant  abounds  especially  in 
spruce  swamps  and  among  tamaracks.  It  is  scarcely  ab- 
sent from  a  single  spruce  swamp  in  the  state.  A  form,  known 
as  the  narrow-leafed  Labrador  tea,  with  much  slenderer  leaves 
than  the  common  species,  grows  along  the  Pigeon  river  in 
24 


354  Minnesota  Plant  Life. 

Cook  county.  From  this  plant,  which  is  fragrant  if  crushed,  the 
oil  known  as  Leduin  oil  is  manufactured. 

Menziesias.  The  Menziesia  is  a  small  shrub,  three  or  four 
feet  in  height,  with  obovate  deciduous  leaves  and  pretty,  nodding 
umbels  of  bell-shaped,  purplish  flowers.  The  calyx  and  corolla 
are  generally  four-lobed  and  there  are  eight  stamens,  while  the 
fruit  is  a  spherical  or  ovoid  capsule,  splitting  into  four  segments. 

Kalmias.  The  laurel  or  Kalmia,  occurs  in  cold  peat-bogs  as 
far  south  as  Gull  lake.  It  is  a  little  shrub,  usually  not  more 


FIG.  169.     Kalmia  flowers.     After  Atkinson. 

than  eighteen  inches  high,  with  opposite,  linear,  evergreen,  pale 
green  leaves.  The  flowers,  borne  in  terminal  umbels,  are  purple 
and  broadly  bowl-shaped,  with  five  marginal  notches  and  ten 
stamens.  The  shape  of  the  flower  will  serve  to  distinguish  this 
plant  from  the  rosemary,  which  somewhat  resembles  it.  On 
the  under  side  the  leaves  are  white. 

Moss-plants,  The  Cassiope  or  "moss-plant,"  is  found  along 
the  palisades  north  of  Duluth,  extending,  doubtless,  to  Grand 
Portage.  It  looks  like  a  moss,  being  densely  tufted,  evergreen, 
and  only  from  one  to  three  inches  in  height.  The  leaves  are 
very  small  and  crowded,  and  the  flowers  are  borne  singly  at  the 
ends  of  leafless  pedicels  arising  from  the  tips  of  branches  or 


Minnesota  Plant  Life. 


355 


from  the  axils  of  the  leaves.  The  flowers  are  white  and  nod- 
ding, and  each  matures  a  spherical  capsule  with  a  large  number 
of  small  seeds.  No  other  plant  in  Minnesota  resembles,  in 
general  habit,  this  tiny  shrub. 

Rosemarys.  The  rosemary,  found  in  cold  peat-bogs  through- 
out the  northern  part  of  the  state,  is  a  shrub  one  or  two  feet  in 
height,  with  few  branches.  The  leaves  are  slender,  willow- 
shaped,  darker  above  than  those  of  the  Kalmia,  but  with  the 
same  white  under  sides  and  incurved  margins.  The  flowers, 
however,  are  nodding  and  vase-shaped,  rather  than  erect! 
spreading  and  bowl-shaped,  as  in  the  Kalmia.  The  capsule  is 
more  nearly  spherical  than  that  of  the  Kalmia. 

Trailing  arbutus.  The  trailing  arbutus  is  a  rare  plant  in 
Minnesota,  occurring, 
however,  near  Duluth 
and  on  the  Kettle  river 
and  in  the  valley  of  the 
St.  Croix.  It  is  a  pros- 
trate, trailing,  branching 
shrub,  with  alternate,  ob- 
long, leathery,  evergreen, 
entire  leaves.  The  blos- 
soms are  pink,  borne  in 
clusters  toward  the  ends 
of  the  branches.  They 
are  sweet-scented  and  mature  into  spherical,  furry,  five-cham- 
bered capsules. 

Checkerberries.  The  checkerberry,  an  abundant  plant  in 
the  pine  woods  throughout  the  northern  part  of  the  state — 
rarely  extending,  also,  as  far  south  as  Lake  Pepin — is  a  little 
shrub  with  slender,  prostrate  or  underground  stems,  from  which 
erect  branches  arise  to  a  height  of  from  two  to  six  inches.  Its 
leaves  are  oval,  slightly  toothed,  evergreen  and  shining,  dark 
above  and  paler  beneath.  The  flowers  nod  in  the  axils  of  the 
leaves  and  are  white,  broadly  vase-shaped,  and  with  five  mar- 
ginal teeth.  The  fruit  is  bright  red  and  of  a  distinctive  agreeable 
flavor.  This  plant  is  also  known  in  Minnesota  as  wintergreen 
and  partridgeberry. 

Bearberries.  The  bearberry,  growing  best  on  sandy  soil,  is 
abundant  through  the  northern  part  of  the  state  and  extends 


FIG.  170.     Moss-plant.    After  Britten  and  Browi 


356  Minnesota  Plant  Life, 

south  very  sparingly  to  Winona  county.  It  is  a  little  trailing 
shrub,  with  leathery  entire,  evergreen,  spoon-shaped  leaves  and 
a  few  small,  white,  vase-shaped  flowers  in  terminal  racemes. 
The  berries  are  red  and  rather  tasteless. 

Leatherleafs.  The  leatherleaf  occurs  in  cold  bogs  from  the 
north  shore  of  Lake  Superior  to  Lake  of  the  Woods,  and  south 
into  the  valley  of  the  St..  Croix.  It  is  a  branching  shrub, 
usually  about  two  feet  in  height.  The  leaves  are  evergreen, 
oblong,  ovate  in  shape,  and  when  young  provided  with  scurfy 
hairs  or  scales  on  both  sides.  The  flowers  are  produced  in  large 
numbers  towards  the  ends  of  the  branches.  Each  flower  nods 
in  the  axil  of  a  leaf,  is  white  and  urn-shaped  and  produces  a 
spherical,  deeply  five-grooved  fruit. 

Blueberries  and  cranberries.  The  blueberries  and  cranber- 
ries, of  which  there  are  about  eleven  varieties  in  the  state, 
include  some  well-known  forms.  Here  are  to  be  classified  the 
bog  huckleberry,  the  dwarf  bilberry,  the  thin-leafed  bilberry, 
the  tall  bilberry,  the  tall  blueberry,  the  Canada  blueberry,  the 
low  blueberry,  the  mountain  cranberry  or  cowberry,  the  deer- 
berry,  the  small  and  the  large  cranberry.  Most  of  these  are 
found  only  in  the  northern  part  the  state,  especially  along  the 
international  boundary  and  the  north  side  of  Lake  Superior, 
extending,  as  so  many  northern  plants  do,  down  the  valley  of 
the  St.  Croix,  through  which  in  early  days  Lake  Superior 
drained  into  the  Mississippi  river. 

Blueberries.  The  different  kinds  of  blueberries  or  bilberries 
are  to  be  discriminated  by  their  foliage  and  by  the  flavor  of  the 
berries.  The  one  most  common  is  the  dwarf  or  low  blueberry, 
gathered  in  large  quantities  for  the  market.  Its  fruits  are 
blue  with  a  whitish  bloom  and  are  of  very  pleasant  flavor, 
enjoyed  alike  by  the  Indians  and  the  whites.  The  plant  is  a 
low  shrub,  with  pale  green  leaves,  not  evergreen.  Its  flowers 
are  vase-shaped,  small,  and  white  or  pink. 

The  deerberry,  which  resembles  the  blueberry  in  some  re- 
spects, is  considerably  larger — three  or  four  feet  in  height.  The 
berries,  shaped  like  the  blueberries,  are  greenish  or  yellow  and 
not  edible.  This  variety  is  also  called  the  squaw  huckleberry. 

The  Canada  blueberry,  found  growing  in  much  moister  soil 
than  the  ordinary  form,  has  smaller  berries,  of  a  blue  color,  with 


Minnesota  Plant  Life. 


357 


a  bloom.  It  may  be  distinguished  by  the  entire  margins  of 
the  leaves,  quite  different  from  the  notched  margins  of  the  low 
blueberry.  The  bog  blueberry  has  pink  flowers  and  small  ovate 
leaves.  The  cowberry  may  be  recognized  by  the  sour  red 
berries  and  the  evergreen  leaves.  The  flowers  and  fruits  are 
in  structure  altogether  similar  to  those  of  the  blueberries. 

Cranberries.  The  two  kinds  of  cranberries  found  in  the 
state  are  both  bog  plants,  with  very  slender  creeping  stems, 
having  small  thick  evergreen  leaves  apparently  disposed  in 
two  rows  along  the 
branches.  In  the  small  cran- 
berry the  berry  is  almost 
spherical,  while  in  the  large 
cranberry  an  oblong  or 
ovoid  berry  is  produced.  In 
the  flowers  the  corolla  lobes 
are  turned  backward  toward 
the  stem.  By  this  character 
the  cranberries  can  be  dis- 
tinguished from  the  cow- 
berry, which  has  a  bell- 
shaped  flower.  Both  spe- 
cies of  cranberry  are  red 
or  spotted,  and  acid  to  the 
taste. 

Snowberries.  The  snow- 
berry  has  a  plant-body  which  reminds  one  of  that  of  the  cran- 
berries, but  the  flowers  are  ovoid  vase-shaped,  and  the  fruit  is 
of  a  pure  white  color.  Like  the  cranberries,  they  are  found  in 
cold  peat-bogs  and  in  tamarack  swamps.  This  plant  is  partic- 
ularly abundant  in  the  region  about  Duluth. 

Huckleberries.  One  variety  of  huckleberry  is  found  between 
the  Kettle  river,  Cass  lake,  and  the  international  boundary. 
The  plant-body  reminds  one  of  the  blueberry,  but  the  fruits  are 
black,  without  a  bloom,  sweet  to  the  taste  and  clustered  in 
erect  or  nodding  racemes. 

Primroses.  The  twenty-eighth  order  comprises  three  fami- 
lies of  plants,  of  which  only  one,  the  primrose  family,  is  repre- 
sented in  the  state.  Of  primroses  there  are  fourteen  or  fifteen 


FIG.  171.    Small  cranberry.    After  Britton  and 
Brown. 


358  Minnesota  Plant  Life. 

Minnesota  species,  including  two  varieties  of  primrose,  one  An- 
drosace,  one  water-pimpernel,  two  loosestrifes,  the  curious  little 
sea-milkwort,  the  poor  man's  weather-glass,  and  the  chaffweeds. 
Besides,  there  is  a  plant  known  as  the  starflower  and  another 
as  the  shooting-star,  both  to  be  classed  in  this  family.  The 
true  primroses  are  found  only  along  the  north  shore  of  Lake 
Superior.  They  are  small  plants,  with  a  tuft  of  rather  long, 
willow-shaped  leaves,  from  the  centre  of  which  a  stem  arises, 
bearing  at  the  tip  a  little  umbel  of  pink  flowers. 

The  Androsace  is  a  tiny  plant,  often  not  more  than  an  inch 
in  height.  It  is  of  about  the  same  size  as  the  little  whitlow- 
grass  of  the  mustard  family.  The  leaves  are  produced  in 
rosettes.  From  these  slender  flowering  axes  arise,  usually  more 
than  one,  and  at  the  end  of  each  of  them  is  an  umbel  of  small 
white  flowers.  This  plant  may  be  distinguished  from  the  whit- 
low-grass by  its  umbels  in  place  of  racemes.  It  is  more  com- 
mon on  prairies  in  the  western  part  of  the  state. 

The  water-pimpernel  grows  near  springs  and  in  the  edges 
of  brooks.  It  is  from  six  to  eighteen  inches  in  height,  some- 
what branched,  with  membranous  oval  leaves.  The  flowers 
are  tiny  and  bell-shaped,  produced  numerously  in  loose  racemes. 
The  calyx  is  blended  with  the  base  of  the  fruit-rudiment  and 
the  seeds  are  very  small.  The  loosestrifes  and  the  false  loose- 
strifes grow  for  the  most  part  in  wet  places  or  in  fields,  and 
may  be  recognized  by  their  bright  yellow,  primrose-like  flow- 
ers. In  some  of  the  varieties  the  leaves  are  in  whorls,  while 
in  others  they  are  opposite.  The  flowers  in  some  sorts  are 
solitary  in  the  axils  of  the  leaves,  but  in  others  they  are  in 
terminal  racemes  or  flat-topped  clusters.  In  one  kind,  the 
tufted  loosestrife,  a  swamp  plant  abundant  throughout  the  state, 
the  yellow  flowers  are  grouped  in  dense  racemes  which  stand 
in  the  axils  of  the  opposite,  willow-shaped  leaves. 

The  starflower  grows  in  deep  woods  along  with  the  dwarf 
cornel  and  the  wintergreens.  It  is  a  little  plant  with  prostrate 
rootstock  from  which  a  slender  stem  rises  to  a  height  of  about 
six  inches  or  less.  Two  or  three  white  star-shaped  flowers  are 
produced  from  the  tip  of  this  stem  and  directly  under  them  are 
from  five  to  ten  willow-shaped,  slender  leaves,  all  standing  in 
a  circle. 


Minnesota  Plant  Life. 

The  sea-milkwort  is  found  in  some  saline  marshes  in  the  Red 
river  valley.  It  is  a  small,  branched  herb,  with  opposite,  fleshy 
leaves,  in  the  axils  of  which  small,  stemless,  pink  or  white  flow- 
ers are  produced.  Each  flower  is  broadly  bell-shaped. 

The  poor  man's  weather-glass  or  scarlet  pimpernel  is  intro- 
duced from  Europe,  in  some  waste  fields.  It  has  the  opposite 
leaves  and  open  tubular  flowers  of  its  family,  but  the  color  of 
the  flowers,  which  are  produced  singly  on  the  stems  in  the  axils 
of  the  leaves,  is  scarlet  or  pink  with  a  darker  centre.  They 
open  only  in  the  sunshine,  hence  the  common  name. 

The  chafrweed,  to  be  met  with  at  the  Pipestone  quarry  in 
Pipestone  county  and  probably  elsewhere  on  rocks  in  the  Min- 
nesota valley,  selects  moist  depressions  and  grows  as  a  little 
branched,  insignificant  herb  with  small,  alternate  entire  leaves, 
in  the  axils  of  which  little  pink,  stemless  flowers  are  produced. 
The  capsule,  when  it  matures,  splits  by  a  circular  cleft,  cutting 
off  its  upper  portion  as  a  lid,  recalling  the  purslanes. 

The  shooting-star  may  be  recognized  at  once  among  all  the 
other  flowering  plants  of  the  state  by  the  curious  position 
which  the  petals  take  in  the  open  flowers.  The  young  flowers 
are  erect,  but  as  they  grow  older  the  flower  is  inverted.  When 
they  open  the  petals  turn  completely  back,  so  that  while  the 
stamens  point  downward,  the  petals,  which  are  of  a  purple  or 
whitish  color,  have  their  tips  directed  upward.  When  this  plant 
begins  to  set  its  fruits,  the  stems  of  the  flowers  straighten  again, 
so  that  the  tips  of  the  young  capsules  point  upward.  The  petals 
of  the  open  flower  are  often  twisted,  giving  to  the  plant  a 
peculiar  and  characteristic  appearance. 


Chapter  XXXVI. 

From  Ash  trees  to  Verbenas* 


The  twenty-ninth  order  includes  four  families,  none  of  which 
is  native  to  Minnesota.  Here  are  grouped  the  persimmon  trees 
of  the  south,  the  benzoin  gum  trees,  the  gutta-perchas  and  the 
butter  seeds,  and  the  ebony  tree,  the  hard  black  wood  of  which 
is  capable  of  taking  a  high  polish  and  is  much  prized. 

The  thirtieth  order  includes  the  ashes,  the  gentians,  the  dog- 
banes and  the  milkweeds,  all  represented  in  the  Minnesota  flora. 
There  are  also  two  other  families  without  Minnesota  represent- 
atives, in  one  of  which  is  classified  the  strychnine  plant. 

The  ash  family,  besides  the  common  ash  trees,  comprises 
also  the  lilac  bushes,  the  olive  trees  and  the  jasmines.  Lilac 
bushes,  with  their  handsome  panicles  of  fragrant  tubular  flowers, 
are  well  known  as  dooryard  shrubs  throughout  the  state.  They 
are  not,  however,  natives  of  North  America. 

Of  ashes  there  are  five  species  in  Minnesota,  namely,  the 
white,  the  red,  the  green,  the  blue  and  the  black.  Ash  trees, 
botanically  considered,  are  noteworthy  as  being  the  highest 
type  of  trees  native  to  the  state.  In  all  of  them  the  leaves  are 
compound,  consisting  of  several  leaflets  arranged  pinnately 
upon  a  common  axis.  The  fruit  in  all  the  varieties  has  a  strong 
terminal  wing,  by  means  of  which  it  is  distributed  in  air  cur- 
rents. The  different  kinds  of  ashes  may  be  known  by  the 
foliage,  the  character  of  the  wing  on  the  fruit,  and  the  appear- 
ance of  the  young  twigs. 

White  ashes.  The  white  ash  is  a  tree,  reaching  under  fa- 
vorable conditions  a  height  of  120  feet,  but  not  growing  so 
strongly  in  Minnesota.  The  bark  is  dark  brown  and  the  wood 
is  heavy,  firm  and  tough,  universally  employed  in  the  manu- 
facture of  tool  handles  and  agricultural  machinery.  The  leaves 
are  composed  usually  of  seven  leaflets,  somewhat  broadly  willow- 


Minnesota  Plant  Life. 

shaped,  dark  green  above  and  light  green  and  often  hairy  below. 
The  body  of  the  fruit  is  cylindrical  and  the  wing  is  terminal, 
not  at  all  or  but  very  slightly  extended  down  the  sides. 

Green  ashes.  The  green  ash  is  a  smaller  tree  than  the  white 
ash,  and  its  wood  is  somewhat  inferior  in  quality,  though  strong. 
The  leaflets  are  similar  to  those  of  the  white  ash,  but  rather 
broader.  The  fruit  is  commonly  winged  down  the  sides.  The 
twigs  and  the  flower  stems  are  smooth  or  only  very  slightly 
hairy. 

Red  ashes.  The  red  ash  is  a  tree  of  about  the  same  height 
as  the  green  ash,  not  exceeding  thirty  or  forty  feet  in  Minne- 
sota. The  twigs  and  flower  stalks  are  covered  with  velvety 
hairs  and  the  fruit  is  generally  winged  down  the  sides. 

Blue  ashes.  The  blue  ash  may  be  recognized  by  the  four- 
sided  young  twigs,  the  smooth  foliage  and  the  leaflets — num- 
bering from  seven  to  eleven, — slender  and  of  a  more  willow- 
shaped  outline  than  in  the  preceding  varieties.  The  fruit  is 
broader,  shorter  and  heavier  in  appearance  than  that  of  the 
white  ash,  and  is  winged  down  the  sides. 

Black  ashes.  The  black  or  elder-leafed  ash,  unlike  the  oth- 
ers, is  a  swamp  tree,  occasionally  growing  also  in  low,  wet 
woods  along  streams.  There  are  from  seven  to  eleven  leaflets 
in  each  leaf,  but  the  twigs  are  cylindrical,  not  four  angled.  Both 
the  blue  and  the  black  ash  are  large  trees,  sometimes  reaching  a 
height  of  a  hundred  feet  or  more.  The  bark  in  both  varieties 
is  of  a  gray  color.  The  wood  of  the  black  ash  is  heavy  but  not 
very  strong,  and  the  tree  is  noticeable  for  the  stemless  character 
of  the  lateral  leaflets,  in  which  respect  it  differs  from  all  the 
other  ashes.  This  tree  is  often  affected  by  an  insect  which  pro- 
duces large  "witches-brooms"  or  galls. 

Ash  flowers  are  rarely  perfect.  Usually  they  are  separated, 
the  staminate  flowers  blooming  on  one  tree  and  the  pistillate 
on  another,  though  in  other  instances  both  separated  and  per- 
fect flowers  are  found  on  the  same  tree.  The  calyx  is  small, 
or  it  may  be  altogether  wanting.  The  corolla,  too,  is  some- 
times lacking.  There  are  usually  two  stamens  inserted  below 
the  fruit-rudiment,  or  on  the  base  of  the  petals  when  they  are 
present,  and  the  stigma  is  two-cleft,  so  that  the  fruit-rudiment 
has  two  chambers,  in  each  of  which  a  couple  of  seed-rudiments 


Minnesota  Plant  Life. 


are  produced.  Only  one  of  the  seed-rudiments  ripens,  so  that 
when  the  fruit  is  mature  it  ordinarily  contains  but  a  single  seed, 
supplied  with  albumen,  and  inclosing  the  straight  embryo  plant- 
let.  The  flowers  are  borne  in  panicled  clusters  and  are  of  a 
greenish  color.  All  five  varieties,  except  the  blue  ash,  are  pretty 
common  in  Minnesota.  The  white  ash  and  the  green  ash  are 
the  most  abundant.  The  red  ash  abounds  particularly  down 
the  upper  Mississippi  to  the  White  Earth  reservation,  and  on 
the  Rainy  river.  The  blue  ash  is  found  only  in  the  far  northern 
portions  of  the  state  along  the  international  boundary  and 

near  the  sources  of  the  Mis- 
sissippi. 

Gentians,  The  gentian 
family  includes  in  Minne- 
sota about  ten  species  of 
gentian,  one  spurred  gen- 
tian, one  buck-bean  and  one 
f  1  o  a  t  i  n  g-heart.  The  two 
plants  last  named  are  either 
aquatic  or  denizens  of  wet 
bogs,  but  the  others  are 
terrestrial.  The  gentians 
proper  are  noted  for  their 
beautiful  blue  flowers, 
blooming  late  in  the  year. 
Two  of  the  ten  varieties  are 
known  as  fringed  gentians, 
because  the  edges  of  the 
lobes  of  the  corolla  tubes  are  frayed  out  into  a  blue  fringe. 
The  larger  fringed  gentian  has  opposite,  stemless,  broad-based 
leaves.  The  smaller  fringed  gentian  has  leaves  slender  at  the 
base  and  narrower,  of  willow-shaped  or  linear  outline.  The 
other  gentians  are  not  fringed.  In  some  the  flowers  open 
into  little  blue  bells,  but  in  one,  known  as  the  closed  gentian, 
the  corolla  does  not  open  at  all,  or  only  by  a  small  pore. 
Of  those  that  open,  the  northern  gentian  may  be  recognized 
by  the  row  of  ragged  threads  which  arise  just  below  and  in- 
side the  notches  of  the  corolla  tube.  The  leaves  are  oppo- 
site and  lance-shaped.  The  stiff  gentian  and  the  oblong-leafed 


FIG.  172.    Yellow  gentian.    After  Britton  and 
Brown. 


Minnesota  Plant  Life. 

gentian  are  very  similar,  but  have  not  the  shredded  filaments 
in  a  circle  within  the  lobes  of  the  corolla.  The  oblong-leafed 
gentian  has  between  each  of  the  five  notches  of  the  corolla 
tube  a  little  ragged,  toothed  appendage.  The  plant-body  is 
smooth.  The  downy  gentian  is  quite  similar  to  the  oblong- 
leafed,  but  may  be  known  by  its  solitary  stems,  while  those  of 
the  oblong-leafed  gentian  are  clustered.  In  all  the  sorts  that 
have  been  mentioned  the  stamens  are  distinct  and  spreading. 
In  the  remaining  varieties  the  stamens  bend  together  and  co- 
here by  their  tips  into  a  ring  around  the  fruit-rudiment.  The 
soapwort  gentian  is  a  form  with  the  flowers  of  the  closed  gen- 
tian and  opening  but  slightly  at  the  tip.  The  leaves  are  oppo- 
site, but  in  the  closed  gentian  they  are  in  whorls  around  the 
clustered  flowers.  The  yellow  gentian  produces  its  bell-shaped 
flowers  at  the  ends  of  stems  or  in  the  axils  of  upper  leaves, 
quite  after  the  mode  of  the  closed  gentian,  but  they  are  of  a 
greenish  or  yellowish  white  instead  of  blue.  The  narrow-leafed 
gentian  somewhat  resembles  the  downy  variety,  but  may  be 
distinguished  by  the  coherence  of  the  stamens  in  a  tube.  The 
leaves  are  slender  and  willow-shaped.  The  red-stemmed  gen- 
tian is  like  this,  with  broad-based,  lance-shaped  leaves. 

Many  of  the  gentians  are  found  in  bogs  or  in  moist  meadows. 
In  the  autumn  of  the  year,  together  with  Parnassias,  they  form 
extensive  beds  in  the  low  wet  meadows  along  river  valleys.  The 
spurred  gentian  has  a  spur  at  the  base  of  each  of  the  corolla 
lobes,  making  the  flower  somewhat  of  the  shape  of  a  colum- 
bine. They  are  rather  smaller,  however,  and  of  a  purplish  or 
white  color.  This  plant  is  found  along  the  north  shore  of  Lake 
Superior  and  throughout  the  northern  part  of  the  state  to  Lake 
of  the  Woods. 

Buck-beans.  The  buck-bean  is  a  pretty  common  plant  on 
floating  bogs  and  among  the  reed-grasses  along  the  shores  of 
lakes.  From  a  thick,  scaly  rootstock  stems  arise,  bearing  leaves 
in  shape  somewhat  like  large  clover  leaves  and  of  a  pale  green 
color.  The  flowers  are  borne  in  panicles  and  are  white  or 
purple,  decidedly  attractive  in  appearance.  This  plant  is  fre- 
quent in  the  Chisago  lakes  and  generally  throughout  the  state. 
In  the  northern  lakes  it  becomes  very  abundant  and  is  often 


364  Minnesota  Plant  Life. 

found  growing  luxuriantly  in  great  beds  almost  to  the  exclu- 
sion of  other  vegetation. 

Floating-hearts,  The  floating-heart  is  an  odd  little  water 
plant  with  a  rootstock  that  creeps  in  the  mud  at  the  bottom 
of  ponds.  There  are  two  sorts  of  leaves.  Those  which  are 
submerged  are  grass-like  and  clustered  around  the  base  of  the 
stems,  which  are  thread-like  and  sometimes  ten  feet  in  length. 
At  the  surface  of  the  water  there  is  borne  a  single  broadly  heart- 
shaped  floating  leaf,  a  little  umbel  of  yellow  flowers,  and  a  clus- 
ter of  curious  tubers.  No  other  plant  in  the  Minnesota  flora  is 
anything  like  the  floating-heart  in  appearance.  The  grouping 
of  a  bunch  of  tubers,  an  umbel  of  yellow  flowers,  and  a  single, 
broad  heart-shaped  floating  leaf  at  the  end  of  a  slender  stem  aris- 
ing from  the  bottom  of  a  pond  will  serve  at  once  to  designate  it. 

Dogbanes,  Three  species  of  dogbanes  exist  in  the  state. 
One  of  them  is  known  as  Indian  hemp.  All  of  them  have 
a  milky  juice,  so  that  they  are  often  mistaken  for  milkweeds. 
They  may  be  recognized,  however,  by  their  flowers,  which  are 
somewhat  bell-shaped  and  do  not  have  the  five  singular,  horn- 
like appendages  of  the  petals  distinctive  of  most  milkweed- 
flowers,  and  connected  with  the  remarkable  pollination-con- 
trivance of  that  family  of  plants.  One  of  the  dogbanes — more 
abundant  in  the  northern  part  of  the  state — has  a  spread- 
ing, generally  forked  stem,  with  opposite  broad  leaves,  and, 
in  loose  terminal  cymes,  white  flowers  which  mature  slender 
cylindrical  pods.  In  these  are  enclosed  a  large  number  of  seeds 
with  tufted  flying-hairs  at  their  ends.  The  Indian  hemp  sends 
up  erect  branches,  but  not  broadly  forked  at  the  summit  like 
those  of  the  spreading  dogbanes.  The  flowers  are  produced 
in  rather  thick  clusters  at  the  apex,  or  arise  from  the  axils  of 
the  leaves.  Still  another  variety  of  dogbane,  with  clasping 
leaves,  occurs  in  the  southern  part  of  the  state. 

Milkweeds.  The  milkweeds  form  a  family  of  plants  with  pods 
and  seeds  like  those  of  the  dogbanes,  but  with  most  extraordi- 
nary flowers,  gathered  in  most  instances  in  umbels,  and  fitted  for 
pollination  by  insects.  These  are  captured  by  the  flowers,  as  if 
in  a  trap,  after  which  pollen  masses  shaped  like  the  old-fashioned 
saddle-bags  are  attached  to  their  legs.  In  Minnesota  there  are  a 
dozen  species  of  ordinary  milkweeds  and  five  green  milkweeds. 


Minnesota  Plant  Life. 


365 


Each  milkweed  flower  consists  of  a  five-parted  calyx,  usually 
small.  Within,  there  appear  the  five  corolla  lobes,  turned  back 
around  the  pedicel  of  the  flower  when  it  opens.  Next  are  five 
curious  hood-shaped  appendages  of  the  corolla,  known  as  the 
corona.  Inside  of  each  hood  is  a  horn-shaped  process,  while 
the  stamens  fuse  together  into  a  tube  around  the  central 
fruit-rudiment.  When  an  insect  visits  the  flower  in  search  of 
honey,  it  catches  its  legs  in  grooves  between  the  hoods  of  the 
corona,  and  in  attempting  to  escape  must  drag  its  feet  over  a 
part  of  the  stamen  where  a  viscid  forked  body  is  located,  and  this 
with  a  couple  of  pollen-masses  attached  to  it  is  pulled  out  of 
the  flower.  By  means  of  a  bit 
of  silk  thread  any  one  can,  with 
proper  care,  extract  the  little 
saddle-bag,  thus  imitating  the 
work  which  the  flower  exacts 
from  its  insect  visitor.  Often 
bees  are  not  strong  enough  to 
jerk  their  legs  free  from  the 
cleft  in  which  they  are  caught, 
and  they  may  sometimes  be 
seen  hanging  head-downward 
from  the  milkweed  flower,  de- 
spondent or  dead. 

The  different  sorts  of  milk- 
weeds in  Minnesota  may  be 
identified  by  the  shapes  of 
their  leaves,  the  colors  of  their 
flowers  and  the  surfaces  of  their  pods.  One  milkweed,  com- 
mon on  prairies,  has  bright  orange  flowers,  and  this  sort  is 
known  as  the  butterfly-weed.  Its  leaves  are  alternate  and  hairy 
and  the  pods  stand  erect  and  are  covered  with  fine  hairs. 
Another  group  of  milkweeds  has  the  flowers  purple  and  the 
leaves  opposite.  Here  are  classified  the  purple  milkweeds, 
with  stout,  smooth  stems  two  feet  or  more  in  height  and  leaves 
of  an  elongated,  pointed  oval  shape.  They  are  found  in  dry 
fields.  The  swamp  milkweed  is  similar  in  appearance,  but  has 
smaller  clusters  of  flowers  and  slenderer  willow-shaped  leaves. 
usually  quite  smooth.  It  is  to  be  looked  for  in  swamps  or 


FIG.  173.     Swamp  milkweed, 
and  Brown. 


After  Britton 


;65 


Minnesota  Plant  Life. 


marshes.  The  hairy  milkweed  is  similar  to  the  swamp  milk- 
weed and  is  found  in  similar  stations,  but  has  very  hairy  leaves. 
In  all  varieties  the  umbels  of  flowers  are  crowded  toward  the 
top  of  the  plant  and  are  erect,  as  are  the  pods. 

Sullivant's  milkweed  and  the  blunt-leafed  milkweed  are 
smooth,  pale  green  plants  with  stout  stems  and  rather  broad, 
blunt  leaves.  The  capsules  in  Sullivant's  milkweed  are  borne 
on  straight  erect  stems,  but  in  the  blunt-leafed  milkweed  the 
downy,  slender  capsules  stand  on  stems  curved  downward  like 
the  letter  "S."  The  tall  milkweed,  or  poke  milkweed,  has 
lance-shaped  leaves  and  the  capsules  stand  erect  upon  pedicels 
which  grow  diagonally  downward.  The  four-leaved  milkweed 

is  recognized 
by  the  leaves 
toward  the  mid- 
dle of  the  stem, 
standing  in 
whorls  of  four. 
Two  m  i  1 k - 
weeds,  known 
as  the  common 
milkweed  and 
the  showy  milk- 
weed, are  dis- 
tinguished by 
the  pods,  the 
surfaces  of 

which  are  covered  with  short,  soft,  somewhat  elongated  tufts 
or  warts.  The  common  milkweed  has  oblong  leaves,  while  the 
showy  milkweed,  named  on  account  of  the  large  purplish-green 
flowers,  has  broad,  ovate  leaves.  Both  these  are  very  prolific 
in  fields  along  roadsides  and  in  damp  places  throughout  the 
state.  The  oval-leafed  milkweed  is  a  plant  of  the  southern  and 
western  prairies.  It  is  recognized  by  its  smaller,  greenish 
flowers  arranged  in  few  or  in  solitary  umbels  toward  the  tip 
of  the  stem.  The  leaves  are  rather  broadly  willow-shaped  and 
cottony  on  both  surfaces.  When  quite  mature  the  upper  sur- 
faces of  the  leaves  become  smooth.  The  whorled  milkweed 
has  very  narrow  leaves  in  whorls  of  from  three  to  seven.  The 
pods  are  slender,  two  or  three  inches  long,  and  smooth. 


FIG.  174.     Brookside  vegetation.     Milkweeds  in  foreground.     After 
photograph  by  Williams. 


Minnesota  Plant  Life. 


36? 


The  green  milkweeds  may  be  distinguished  by  this  character: 
The  hoods  of  the  corona  do  not  inclose  spur-like  projections. 
Otherwise  the  flowers,  flower-clusters  and  pods  are  very  much 
like  those  of  the  true  milkweeds.  Here  are  classified  the  broad- 
leafed  green  milkweeds,  with  lance-shaped  or  broad  willow- 
shaped  leaves;  the  Florida  milkweed,  with  slender,  willow- 
shaped  leaves,  difficult  to  distinguish  from  the  two  varieties  of 
the  broad-leafed  form — in  one  of  which  the  leaves  are  really 
grass-shaped,  while  in  the  other  they  are  lance-shaped.  The 
broad-leafed  milkweed  and  its  varieties  have,  however,  sessile 
umbels  of  flowers,  while  the  Florida  milkweed  displays  each 
umbel  on  a  stem  of  its  own.  Besides  the  varieties  of  green 
milkweed  which  have  been  mentioned,  there  is  another  known 
as  the  woolly  green  milkweed.  It  is  characterized  by  a  solitary 
terminal  umbel  and  woolly  or  hairy  leaves,  and  is  found  on 
prairies. 

The  thirty-first  order  includes  a  number  of  families,  most 
of  which  are  represented  in  Minnesota.  Here  are  the  morning- 
glory  family,  to  which  the  morning-glories,  sweet  potatoes  and 
dodders  belong ;  the  phloxes ;  the  waterleafs ;  the  borages ;  the 
verbenas;  the  mints;  the  nightshades,  including  the  ground- 
cherries,  capsicums,  potatoes,  tomatoes,  tobaccos  and  petunias ; 
the  figworts,  with  the  snapdragons,  mulleins,  hyssops  and  fox- 
gloves ;  the  bignonias,  with  the  catalpa  trees ;  the  broom-rapes, 
a  curious  group  of  parasitic  plants ;  the  Gesneras,  to  which  the 
Gloxinias  belong;  the  bladderworts ;  the  Acanthuses;  and  the 
lopseeds.  Several  families,  including  some  of  those  mentioned, 
have  no  species  native  to  Minnesota.  The  following,  however, 
present  Minnesota  forms :  The  morning-glories,  phloxes,  wa- 
ter-leafs, borages,  verbenas,  mints,  nightshades,  figworts,  broom- 
rapes,  bladderworts  and  lopseeds. 

Morning-glories.  The  morning-glory  family  is  represented 
in  Minnesota  by  three  species  of  morning-glory  or  bindweeds 
and  five  species  of  dodder.  The  morning-glories  are  recog- 
nized at  once  by  their  familiar  funnel-shaped  flowers.  In  two 
of  the  varieties  the  stem  is  twining  or  trailing,  while  in  the  erect 
morning-glory  it  stands  independently  and  does  not  twine. 
except  sometimes  very  slightly  at  the  tip.  One  of  the  climb- 
ing morning-glories  has  arrow-head-shaped  leaves  and  pink 


368 


Minnesota  Plant  Life. 


flowers  about  two  inches  long.  The  other  variety  has  ovate, 
blunt-pointed  leaves,  often  very  large  and  somewhat  heart- 
shaped  at  the  base.  The  form  with  the  arrow-head-shaped 
leaves  is  much  more  common  and  is  found  trailing  over  shrub- 
bery in  thickets  or  in  the  edges  of  woods. 

Dodders.  Dodders  are  very  curious  parasitic  plants,  closely 
related  to  the  morning-glories.  They  may  be  considered  as 
twining  morning-glories  which  have  acquired  the  habit  of  suck- 
ing up  their  food 
from  the  bodies 
of  the  plants 
upon  which  they 
climb.  As  a 
consequence  of 
this  habit  their 
leaves  have  been 
reduced  to  tiny 
scales,  being  no 
more  employed 
in  starch-mak- 
ing, and  their 
stems,  no  longer 
green,  have  be- 
come yellow  or 
white  in  color. 
Dodder  often 
produces  great 

FIG.  175.     Dodder  in  flower;  the  parasite  is  seen  to  be  clutching 

tightly  the  stem  of  its  host  plant.      After  Atkinson.  of     threads,     like 

so  much  yellow 

yarn,  looping  over  the  herbs  or  shrubs  from  the  tissues  of  which 
they  extract  their  nutriment.  Another  variety  of  dodder  that 
grows  on  the  stems  of  sunflowers,  goldenrods  and  asters,  looks 
like  three  or  four  turns  of  rope  around  the  axis  of  the  host  plant. 
The  relationship  of  the  dodders  to  the  morning-glories  may 
be  seen  in  their  capsules  and  seeds  which  strongly  bring  to 
mind  the  well-known  pods  of  the  ordinary  cultivated  morn- 
ing-glory. In  Minnesota  the  following  varieties  of  dodder  may 
be  distinguished:  The  field  dodder,  with  sepals  of  the  calyx 


Minnesota  Plant  Life. 


369 


united  into  a  tube,  sessile  flowers,  fringed  corolla  scales  and 
obtuse  calyx  lobes,  the  stems  pale  yellow  and  thread-like,  with 
the  flowers  in  little  clusters ;  the  smartweed  dodder,  most  abun- 
dant on  smartweeds,  similar  to  the  field  dodder,  but  with  the 
thread-like  stems  of  an  orange-yellow  color  and  the  calyx  lobes 
acute;  Choisy's  dodder,  developing  stemmed  flowers  with  dis- 
tinct corollas,  the  lobes  of  which  are  curved  in  over  the  capsule ; 
the  hazel  dodder,  growing  mostly  upon  hazel  bushes,  with  cap- 
sules capped  by  the  shriveling  corolla ;  the  button-bush  dodder, 
with  corolla  lobes  spreading,  not  curved  over  the  capsules,  and 
the  capsule  flattened  and  globular  in  form ;  and  Gronovius' 
dodder,  found,  like  the  button-bush  dodder,  on  a  variety  of 
herbs  and  shrubs,  but  with  pointed  capsules.  In  all  these  dod- 
ders the  flowers  are  in  rather  loose  clusters,  when  compared 
with  the  remaining  variety,  known  as  the  massive  dodder.  In 
this  species,  occurring  mostly  on  goldenrods,  asters,  sunflowers 
and  other  herbs  of  the  composite  family,  the  flowers  are  borne 
in  very  large  numbers  and  very  close  together,  quite  concealing 
the  stem.  The  little  dodder  flower-clusters,  therefore,  give  the 
appearance  of  a  coil  of  rope,  turned  three  or  four  times  around 
the  axis  of  the  host-plant. 

The  stems  of  all  the  dodders  have  sucking  organs  which 
are  driven  through  the  skins  of  their  host-plants  and  expose 
their  surfaces  in  the  soft  tissues.  Through  them  the  juices  of 
the  host-plant  are  absorbed  for  the  benefit  of  the  dodder.  This 
kind  of  parasitism  is  derived  from  the  habit  of  twining  orig- 
inated by  those  prototypes  of  the  dodders,  the  morning-glories. 
It  is  interesting  to  notice  just  how  the  parasitic  habit  probably 
arose  in  this  instance,  because,  in  others,  parasitism  began  in 
quite  different  ways. 

Phloxes.  The  phlox  family  includes  the  Greek  valerians, 
phloxes,  Gilias  and  Collomias.  In  all  the  Minnesota  varieties 
the  flowers  are  tubular,  with  the  lobes  of  the  corolla  spreading. 
The  fruit-rudiments  are  three-chambered,  maturing  into  three- 
chambered  capsules.  Four  sorts  of  phlox  occur  in  Minnesota: 
The  wild  sweet-william,  the  downy,  the  blue,  and  the  smooth 
phlox.  They  are  distinguished  by  the  shapes  and  textures  of 
their  leaves  and  by  the  colors  of  the  flowers. 
25 


370 


Minnesota  Plant  Life. 


In  the  blue  phlox  the  flowers  are  blue  and  each  petal  lobe 
is  notched  at  the  end.  The  other  phloxes  have  pink,  white 
or  purple  flowers.  Of  them,  the  downy  phlox  is  soft,  velvety, 
hairy  or  downy  to  the  touch.  The  smooth  phlox  is  quite 
smooth  with  pink  flowers  and  the  lobes  of  the  corolla  are  longer 
than  the  tube.  The  wild  sweet-william,  or  common  phlox, 
looks  like  the  smooth  phlox,  but  has  flowers  in  which  the  lobes 
of  the  corolla  are  considerably  shorter  than  the  tube.  In  all 
the  phloxes  the  leaves  are  simple,  not  lobed.  The  Polemonium 
has  the  flowers  of  a  phlox,  blue  in  color;  but  the  leaves  are 
pinnately  compound  like  those  of  the  ash.  It  is  an  herb 

about  a  foot  high,  with  weak 
ascending  stem  arising  from  a 
short  rootstock.  The  Collomia 
has  flowers  of  the  phlox  type, 
ag"gre§"ated  in  clusters  at  the 
tips  of  the  stem.  They  are 
purplish  or  white,  but  the 
leaves  are  alternate,  not  oppo- 
site as  in  the  phloxes.  The 
little  Gilia  of  the  western  edge 
of  the  state,  where  it  is  found 
on  high  prairies  near  Lake 
Benton,  is  a  tufted  plant  with 
flowers  in  dense  heads,  each 
provided  with  a  calyx,  the 
lobes  of  which  are  awl-shaped 
and  come  up  around  the  co- 
rolla like  five  stiff  bristles.  The  leaves  are  small,  pinnate  and 
spiny. 

Waterleafs,  The  waterleaf  family  includes  two  waterleafs, 
one  Ellisia  and  two  Phacelias.  The  waterleafs  are  herbs  with 
large,  pinnately  cleft  leaves  and  violet  or  purplish  flowers  devel- 
oped in  umbels  or  cymes.  They  are  exceedingly  abundant  on 
the  level,  damp  floors  of  woods  along  streams  through  the  south- 
ern part  of  the  state.  The  Virginia  waterleaf  has  the  stamens 
a  good  deal  longer  than  the  corolla  and  the  stamen-stalks  are 
hairy.  The  other  waterleaf,  called  the  appendaged  waterleaf, 
has  stamens  but  very  little  longer  than  the  corolla.  Another 


FIG.  176.     Virginia  water-leaf 
and  Brown. 


After  Britton 


Minnesota  Plant  Life.  . 

way  of  distinguishing  the  two  varieties  is  by  the  calyx  which 
in  both  is  five-notched,  but  in  the  appenclaged  waterleaf  a 
little  scale  grows  out  of  each  of  the  calyx  notches,  while  this 
scale  is  absent  in  the  Virginia  waterleaf. 

The  Ellisia  is  an  herb,  four  inches  or  so  in  height,  with  leaves 
a  couple  of  inches  long,  deeply  pinnately-lobed,  shaped  some- 
what like  those  of  the  shepherd's-purse.  The  flowers  are  borne 
singly  on  their  stems,  and  are  white  and  bell-shaped.  In  fruit 
the  calyx  enlarges  and  looks  like  a  small  paper  star,  in  the 
middle  of  which  the  globular  capsule  is  attached.  The  two 
Phacelias,  both  very  rare  plants  in  Minnesota,  have  leaves  some- 
what like  those  of  the  Ellisia,  but  with  purple  or  blue  flowers 
in  clusters.  One  sort  has  them  in  terminal  racemes,  on  both 
sides  of  which  the  flowers  are  borne.  In  the  other  kind  the 
flowers  are  all  grouped  on  one  side  of  the  raceme. 

Borages.  The  borage  family  includes  the  comfreys,  false 
gromwells,  puccoons.  lungworts,  forget-me-nots,  stickseeds, 
hound's-tongues  and  mudworts.  Several  of  the  varieties  are 
introduced  from  Europe.  There  are,  in  all,  about  twenty-five 
varieties  growing  wild  within  the  limits  of  the  state.  Borage 
flowers,  in  outward  appearance,  are  a  good  deal  like  those  of 
the  phlox,  though  often  very  much  smaller.  The  stamens  are 
borne  upon  the  tube  of  the  corolla  and  the  fruit-rudiment,  made 
up  of  two  carpels,  is  deeply  grooved,  so  that  when  the  fruit 
matures  it  has  the  appearance  of  four  one-seeded  nutlets  stand- 
ing close  together  within  the  calyx.  The  leaves  are  generally 
alternate.  The  stems  are  rarely  square,  but  in  almost  every  in- 
stance cylindrical.  The  whole  plant-body  is  commonly  hairy, 
sometimes  very  much  so.  Plants  with  the  sort  of  tubular,  flaring- 
topped  flowers,  found  in  the  sweet-william,  and  accustomed 
to  ripen  four  little  hard  nutlets  from  each  flower,  may  pretty 
safely  be  put  down  as  borages,  unless  their  stems  are  square, 
in  which  instance  they  should  be  looked  for  in  the  mint  family. 

Hound's-tongues.  The  hound's-tongue  is  a  weed  of  waste 
places  and  woods,  with  stems  from  one  to  three  feet  in  height. 
The  flowers  are  blue  or  reddish-purple  and  occur  in  somewhat 
flat-topped  clusters.  Another  sort  of  hound's-tongue,  with 
much  slenderer,  almost  willow-shaped  leaves,  is  an  immigrant 
from  Europe.  Its  flowers  are  arranged,  in  most  instances,  in 


372  Minnesota  Plant  Life. 

one-sided  racemes,  and  these  clusters  show  a  tendency  to  bend 
over  like  a  shepherd's  crook. 

Stickseeds.  The  stickseeds  are  very  abundant  plants  in  the 
Minnesota  woods.  Four  or  five  varieties  exist,  distinguished 
by  the  shapes  of  their  leaves  and  the  character  of  the  flower- 
clusters.  In  all  of  them  the  four  nutlets,  which  constitute  each 
fruit,  separate  from  each  other,  and  on  their  backs  carry  a  num- 
ber of  barbed  hairs,  or  thorns,  by  which  they  attach  themselves 
to  the  fur  of  animals,  or  to  the  clothing  of  man,  thus  obtaining 
distribution.  Among  the  various  little  fruits  and  seeds  which 
anchor  themselves  to  one's  clothing,  in  the  woods,  those  of  the 
stickseeds  may  always  be  known  because  they  are  shaped 
something  like  the  quarter  of  an  apple  and  come  in  groups  of 
four.  The  tip  of  each  of  the  thorns  along  the  backs  of  these 
nutlets  is  barbed  just  like  a  harpoon,  so  that  when  the  burs 
affix  themselves  to  clothing  it  is  difficult  to  remove  them. 
Of  the  Minnesota  varieties,  two  are  very  rare  and  are  known 
to  occur  only  in  the  extreme  northwestern  corner  of  the  state. 
The  others,  however,  are  abundant  throughout  all  portions. 

Lungworts.  The  lungworts  are  also  called  bluebells,  but 
they  are  not  to  be  confused  with  the  Canterbury-bells,  which 
belong  to  quite  a  different  family.  They  are  erect,  smooth  or 
downy  herbs  and  have  blue,  bell-shaped  flowers  with  somewhat 
narrowed  tubes.  The  flowers  are  borne  in  large  terminal, 
hemispherical  clusters,  sometimes  flattened  out  and  loose  in 
appearance.  The  tall  lungwort  possesses  rough  leaves,  while 
the  Virginia  lungwort  has  its  foliage  quite  smooth. 

Forget-me-nots.  Two  sorts  of  forget-me-nots  occur  in  the 
state.  They  are  little,  low,  rough-leaved  plants,  in  one  variety 
with  small  blue  flowers,  and  in  the  other  with  white.  They  are 
annual  or  biennial  and  produce  tufts  of  leaves  near  the  base, 
from  which  the  leafy  flowering  stem  arises.  The  flowers  are 
borne  in  one  or  two-sided  racemes,  often  bent  over  like  a  shep- 
herd's crook. 

Puccoons.  The  puccoons  are  known  by  their  yellow  flowers, 
varying  towards  orange  or  white.  One  of  the  commonest  early 
spring  flowers — the  hoary  puccoon — is  classified  here.  In  this 
plant,  at  the  end  of  the  stem,  six  inches  or  more  in  height,  a 
little  cluster  of  orange  yellow  flowers  is  developed.  When  it 


Minnesota  Plant  Life. 


373 


fruits,  four  white,  hard,  smooth  and  shining  nutlets  are  pro- 
duced, protected  by  the  five-lobed,  green  and  hairy  calyx.  The 
yellow  puccoon,  a  form  that  is  abundant  on  prairies,  has  trum- 
pet-shaped flowers  of  a  lemon  or  bright  yellow  color.  Its  leaves 
are  slenderer  than  those  of  the  hoary  puccoon  and  have  not 
the  same  white-hairy  appearance,  though  they  are  rough  to  the 
touch.  This  plant,  later  in  the  season,  produces  much  smaller, 
pale  yellow,  closed  flowers,  which,  after  pollination  by  their  own 
pollen,  mature  fruits.  The  broad-leafed  puccoon  has  ovate  or 
ovate-lanceolate  leaves  and  may  be  thus  distinguished.  Its 
flowers  are  yellowish-white  or 
yellow.  The  European  puc- 
coon has  yellowish-white  flow- 
ers scattered  along  the  ends  of 
its  branches,  but  it  matures 
the  same  white  hard  nutlets 
that  characterize  its  American 
relatives. 

False  gromwells.  The  two 
species  of  false  gromwell  may 
be  known  by  their  extra- 
ordinarily rough  and  hairy 
foliage,  strong-veined  leaves 
and  inconspicuous  white  or 
greenish  flowers,  produced  in 
leafy  one-sided  racemes.  There 
are  four  nutlets  begun  in  the 
flowers  of  the  false  gromwell,  but  only  one  of  them  is 
likely  to  mature,  so  that  if  ripened  fruiting  specimens  alone 
were  at  hand,  it  would  be  difficult,  at  first  sight,  to  include  these 
plants  in  the  borage  family.  The  nutlets  are  white  and  hard, 
like  those  of  the  puccoons. 

Bonesets.    The  comfrey  or  boneset  has  purple  or  yellow  flow- 
ers, brown  nutlets,  lance-shaped  leaves,  hairy  foliage  and  thick 

roots. 

Verbenas.     The  verbena  family  includes,  in   Minnesota,  six 
varieties  of  wild  verbena  and  one  variety  of  fogfruit,  or 
These  are  all  herbs,  with,  ordinarily,  opposite  leaves  and 
very  much  like  those  of  the  borages,  but  collected  in  spikes  or 


FIG.  177.    Blue  verbena.    After  Britton  and 
Brown. 


374  Minnesota  Plant  Life. 

heads,  and  not  in  one-sided  racemes.  The  fogfruits  have  two- 
lipped  flowers,  and  it  is  doubtful  whether  any  of  them  actually 
occur  in  Minnesota.  The  fruits  of  the  verbenas,  when  mature, 
separate  into  four  nutlets,  just  as  do  the  fruits  of  the  borages. 
If  there  is  any  question  whether  a  plant  is  a  verbena  or  a  borage 
it  may  generally  be  decided  by  opening  the  corolla  tube  and 
counting  the  stamens  adherent  to  its  inner  surface.  If  there 
are  four,  the  plant  is  a  verbena ;  if  there  are  five,  it  is  a  borage. 
Of  course  there  are  a  great  many  other  kinds  of  plants  with 
four  stamens,  but  the  combination  of  four  stamens  on  the  corolla 
tube,  flowers  in  racemes,  spikes  or  heads,  and  fruits  consisting 
of  four  nutlets,  pretty  distinctly  indicates  a  verbena. 

The  six  verbenas  of  Minnesota  may  be  distinguished  as 
follows :  One  of  them  is  a  mat  plant,  growing  in  waste 
fields  along  roadsides  and  on  prairies.  The  whole  plant-body 
is  prostrate  and  often  spreads  out  over  a  circle  a  yard  in 
diameter.  The  flowers  are  purplish-blue  and  borne  in  spikes. 
The  leaves  are  of  various  shapes,  but  some  of  them,  at  least, 
are  likely  to  be  cut,  from  the  margin  toward  the  midrib,  by 
deep  notches.  The  hoary  verbena  is  recognized  by  the  soft, 
hairy  leaves,  of  an  ovate  form,  almost  stemless,  with  the  edges 
sharply  notched.  The  blue  flowers  stand  in  dense  leafy  spikes. 
No  other  verbena  has  this  soft  hairy  leaf-surface.  The  nettle- 
leafed  verbena  and  the  wild  blue  verbena  also  have  ovate  cr 
oblong  leaves,  but  in  these  varieties  each  leaf  has  a  distinct  stem. 
The  nettle-leafed  verbena  has  usually  white  flowers  or  pale 
blue,  while  the  blue  verbena,  as  its  name  indicates,  produces 
bright  blue  flowers.  The  other  two  verbenas  have  different 
foliage  from  the  erect  forms  that  have  been  mentioned.  The 
narrow-leafed  verbena  ~has  very  slender,  or  at  most,  willow- 
shaped  leaves  with  blue  flowers  in  slender,  dense  spikes.  The 
European  verbena,  with  an  erect  habit,  has,  at  least  on  the  lower 
part  of  its  stem,  leaves  deeply  toothed  to  the  midrib,  like  those 
of  the  prostrate  verbena.  The  flowers  are  purple  or  white, 
produced  in  numerous,  very  slender  spikes,  three  to  six  inches 
in  length. 


Chapter  XXXVII. 


From  Peppermints  to  Plantains. 
if 

The  mint  family  in  Minnesota  includes  about  forty  species, 
among  which  are  the  pennyroyals,  mints,  peppermints,  bugle- 
weeds,  basils,  calamints,  horse- 
mints  or  bergamots,  Blephilias, 
catnips,  anise  plants,  hyssops, 
dragon's-heads,  skull-  caps, 
hedge-nettles  and  dead-net- 
tles. 

Mints  may  be  recognized  by 
characters  as  follows:  Their 
stems  are  almost  always  four- 
sided  with  opposite  leaves  and 
aromatic  foliage.  The  flowers 
are  usually  strongly  two- 
\  lipped,  though  in  some  Minne- 
sota varieties  they  are  nearly 
regular.  The  stamens,  borne 
on  the  inner  surface  of  the 
corolla  tube,  are  generally  four 
in  number,  two  of  them  longer 

than  the  other  two;  but  sometimes  the  short  ones  become 
reduced  to  thread-like  appendages.  The  fruit,  as  in  borages 
and  verbenas,  consists  of  four  one-seeded  nutlets.  It  is  almost 
always  possible  to  identify  a  mint  by  rubbing  a  little  of  the 
foliage  between  the  fingers  and  noticing  the  fragrant  odor,  like 
that  of  catnip  or  peppermint.  The  presence  of  the  scent,  even 
if  the  flowers  are  regular  instead  of  two-lipped,  will  serve  to 
indicate  the  mint,  especially  if  its  stem  is  four-sided. 

Wood-sages.     Among  the  mints  some  varieties  may  be  iden- 
tified  by   characters   not   too   minute.     The   wood-sages   and 


FIG.  178.     Wild  mint.     Aftei   Briitou  and 
Brown. 


376 


Minnesota  Plant  Life. 


false  pennyroyals  have  the  fruit-rudiment  lobed  into  four  sec- 
tions, but  not  fairly  divided  into  four  nutlets  as  in  the  rest  of 
the  mints.  The  wood-sage  is  a  slender  herb  from  one  to  two 
feet  tall,  and  is  to  be  looked  for  in  thickets  through  the  southern 
part  of  the  state  and  in  the  Red  river  valley.  The  flowers  are 
distinctly  two-lipped.  The  false  pennyroyal  is  of  similar  habit, 
six  inches  or  more  in  height.  The  flowers  are  small,  blue, 
almost  regular,  and  disposed  in  flat-topped  clusters  arising  from 
the  axils  of  the  leaves. 

Skullcaps.  Of  those  mints  which  separate  their  fruit-rudi- 
ment into  four 
nutlets,  the 
skullcaps  may 
be  known  by 
the  curious  lit- 
tle bulging  pro- 
tuberance upon 
the  back  of  each 
flower.  Skull- 
caps are,  for  the 
most  part,  small 
herbs,  with 
leaves  of  vari- 
ous shapes,  and 
strongly  two-- 
lipped flowers, 

generally     Ol     a          FlQ    17g      clump  Of  horse-mint  (in  middle  of  picture).     After 
blue     COlor.  photograph  by  Williams. 

Four  kinds  occur  in  Minnesota. 

The  rest  of  the  mints  may  be  divided  into  two  series.  In 
one  the  corollas  are  two-lipped,  and  the  upper  lip  is  con- 
cave. Here  are  included  the  catnips,  the  dragon's-heads, 
the  heal-alls,  the  false  dragon's-heads,  the  hedge-nettles  and 
hemp-nettles,  in  all  of  which  there  are  four  stamens  with  pollen 
pouches.  The  sages,  horsemints  and  Blephilias  have  the  same 
kind  of  corolla  but  only  two  of  the  stamens  produce  any  pollen 
pouches.  The  other  series  of  mints  includes  those  forms  in 
which  the  corolla  tube  is  nearly  regular,  or,  if  two-lipped,  has 
the  upper  lip  flat  or  but  very  little  concave.  Here  are  to  be 


Minnesota  Plant  Life. 


377 


grouped  the  pennyroyals,  the  basils,  the  hyssops,  the  mountain- 
mints,  water-hoarhounds  and  peppermints,  in  all  of  which  the 
flowers  are  clustered  in  small  dense  whorls  in  the  axils  of  the 
leaves.  Sometimes,  when  many  of  these  whorls  arise  close  to- 
gether, near  the  end  of  the  stem,  they  become  confluent  into  a 
spike. 

Horsemints  and  dragon's-heads.  Of  the  various  mints  several 
are  decidedly  handsome  plants.  The  horsemint,  for  example, 
with  its  heads  of  two-lipped  flowers,  is  an  abundant  and  beau- 
tiful herb  of  the  woods.  There  are  two  sorts  in  Minnesota, 
one  with  a  yellowish  flower  and  the  other  with  pinkish  or 
purplish  heads.  The  dragon's- 
heads,  with  their  light  blue 
flowers  in  close  clusters  and 
the  false  dragon's-heads  with 
rose-colored  flowers  are  inter- 
esting plants  of  the  northern 
and  central  portions  of  the 
state.  The  water-mints,  found 
in  great  abundance  in  springs 
and  along  the  edges  of  brooks, 
present  a  variety  of  forms, 
many  of  which,  except  by  mi- 
nute characters,  are  difficult  to 
distinguish  from  each  other. 

Some  mint  flowers  are  very 
interesting  mechanisms  for  the 
utilization  of  insects  in  the 
work  of  pollination.  In  the 

sages,  for  example,  the  two  stamens  are  hung  on  levers  and 
rest  under  the  arched  upper  lip  of  the  flower.  When  a  bee 
visits  the  flower  it  stands  upon  the  lower  lip  and  thrusts  its  bill 
down  towards  the  base  of  the  flower,  as  it  does  so,  striking  with 
its  head  the  short  arms  of  the  levers.  The  two  long  arms 
bearing  the  pollen  pouches  are  thus  brought  down  on  the  back 
of  the  insect  like  hammers,  leaving  there  a  couple  of  patches 
of  pollen  spores,  several  hundred  spores  in  each  patch.  After 
this  mechanism  of  the  flower  has  been  set  in  motion  by  the 
visit  of  a  bee,  the  slender  stigma-stalk  of  the  pistil  drops  down 


FIG.  180. 


Horse-mint.    After  Britton  and 
Brown. 


378 


Minnesota  Plant  Life. 


from  the  hood  where  it  was  resting  and  takes  such  a  position 
that  its  end  will  be  dragged  across  the  back  of  a  bee  that  sub- 
sequently visits  the  flower.  In  this  way  bees  going  from  flower 
to  flower  commonly  carry  pollen  from  one  plant  to  stigmas 
of  another. 

Mint  extracts,  as  is  well  known,  are  of  considerable  excel- 
lence for  a  variety  of  purposes.  They  are  used  in  perfumery 
and  confectionery,  and  in  some  medical  preparations.  Many 
of  them  are  gathered  as  household  remedies. 

Ground-cherries.  The  nightshade  or  tobacco  family  includes 
about  fifteen  Minnesota  varieties,  of  which  only  eight  are  native. 
Here  are  the  ground-cherries,  plants  known  also  as  ground 
tomatoes,  and  recognized  by  the  much  inflated  bladdery  calyx, 
which  incloses  the  little  tomato-like  berry.  The  name  ground- 
cherry  is  given  because,  in  the  common  species,  the  berry  is 
about  the  size  of  an  ordinary  cherry.  Several  different  kinds 
occur  in  Minnesota.  The  various  sorts  may  be  known  by  the 
presence  or  absence  of  underground  stems,  by  the  smoothness 
or  hairiness  of  the  leaves,  and  also  by  the  shapes  of  the  leaves, 
by  the  color  and  sizes  of  the  flowers,  and  by  the  shape  of  the 
calyx  in  fruit.  The  most  common  species  in  Minnesota  are  the 
clammy,  the  leaves  of  which  are  clammy  and  viscid  to  the  touch ; 
the  Virginia,  with  smooth  leaves,  sometimes  more  or  less  hairy ; 
the  prairie ;  the  long-leafed,  and  the  Philadelphia  ground-cherry, 
all  of  which  have  underground  rootstocks.  Besides,  there  occur 
the  low,  and  the  cut-leafed,  in  the  first  of  which  the  leaves  are 
ovate  and  entire,  while  in  the  second  the  margins  are  strongly 
notched.  In  neither  of  these  plants  is  there  any  underground 
rootstock  and  the  plants  are  therefore  annual,  springing  up  each 
year  from  the  seed. 

Nightshades.  Besides  the  ground-cherries  there  are  three 
varieties  of  nightshade — herbs  with  flowers  resembling  those 
of  the  potato  and  arranged  in  cymes.  The  black  or  deadly 
nightshade  is  an  annual,  smooth,  unpleasant-smelling  herb,  with 
entire  or  slightly  notched  ovate  leaves,  and  black,  spherical, 
smooth  berries,  without  a  bloom,  hanging  on  nodding  stems. 
The  cut-leafed  nightshade,  which  in  its  fruits  resembles  the  or- 
dinary variety,  may  be  known  by  the  pinnately-lobed  leaves  and 
the  greenish-black  or  green  colored  fruits.  The  prickly  night- 


Minnesota  Plant  Life.  379 

shade,  or  potato-bug  plant,  is  covered  over  with  prickles  both 
upon  the  leaves  and  upon  the  stem.  Even  the  berry  is  very 
prickly.  This  plant,  having  been  introduced  from  the  west, 
is  sometimes  found  along  railway  tracks,  and  it  has  the  unen- 
viable distinction  of  being  the  original  food  of  the  potato-bug. 
From  it,  a  few  decades  ago,  when  potato  cultivation  began  to 
be  undertaken  in  Iowa  and  Nebraska,  this  destructive  insect 
migrated  to  the  fields.  The  climbing  nightshade  has  stems 
from  two  to  eight  feet  long.  The  leaves  are  heart-shaped,  often 
with  two  leaflets  at  the  base.  The  flowers  are  bluish  in  appear- 
ance and  like  those  of  the  potato  or  tomato,  while  the  berry  is 
red  and  as  large  as  the  end  of  one's  thumb. 

Jimson-weeds.  The  jimson-weeds,  which  occur  sparingly  as 
introduced  forms  in  the  southern  part  of  the  state,  are  tall, 
unpleasant-smelling  herbs,  usually  three  or  four  feet  high.  The 
flowers  are  large,  sometimes  two  inches  broad,  shaped  rather 
like  morning-glory  flowers,  but  more  deeply  notched  along  the 
edge.  The  capsule,  an  inch  in  length,  is  prickly  and  bursts 
irregularly. 

Wild  tobacco.  Wild  tobacco  is  found  in  the  vicinity  of  In- 
dian reservations,  having  escaped  from  their  fields.  The  flow- 
ers are  petunia-like  and  the  leaves  are  broadly  ovate  and  smooth 
along  the  edge.  A  many-seeded  capsule,  splitting  longitudi- 
nally into  two  halves,  forms  the  fruit. 

Figworts.  Nearly  fifty  different  varieties  of  figworts  are 
known  to  occur  in  Minnesota.  Here  are  classified  the  mulleins, 
the  toad-flaxes,  the  turtle-heads,  the  monkeyflowers  and  snap- 
dragons, the  false  pimpernel,  speedwells,  Gerardias,  Indian  pinks, 
cow-wheats,  louseworts  and  yellow-rattles.  Figworts  may  be  dis- 
tinguished from  mints,  for  which  they  might  be  mistaken,  by 
their  generally  cylindrical  stems  and  their  two-chambered,  or 
rarely  one-chambered  capsular  fruits,  different  in  appearance 
from  the  deeply  four-lobed,  or  four-nutleted  fruits  of  the  mints. 
Mullein  fruits  are,  in  their  structure,  typical  of  the  figwort 
family.  The  flowers,  however,  are,  for  the  most  part,  strongly 
two-lipped,  recalling  those  of  the  mints,  but  the  aromatic, 
minty  odor  is  absent. 

Mulleins.  Mulleins — common  plants  in  fields  and  pastures 
— are  well-known  on  account  of  their  woolly  leaves,  which 


380 


Minnesota  Plant  Life. 


have  much  the  feeling  of  flannel.  A  careful  examination  of 
a  mullein  leaf  will  show  that  its  surface  is  covered  with  little, 
much-branched  hairs,  standing  close  together  like  so  much 
miniature  shrubbery.  In  the  spring  of  the  year  the  leaves 
form  dense  rosettes  at  the  surface  of  the  ground,  and  later  an 
erect,  tall  flowering  axis  is  developed,  from  two  to  six  feet  in 
height.  At  the  end  of  this  a  spike  of  yellow,  almost  regu- 
lar flowers  is  borne.  In  each  flower  there  are  five  stamens. 


FIG.  181.     View  in  Minnesota  lake  district.     Shows  in  center  two  mullein  plants  in  character 
istic  positions.    After  photograph  by  Williams. 

The  leaves  are  alternate.  In  these  characters  the  mulleins 
differ  from  the  rest  of  the  figworts,  in  none  of  which  are  there 
five  pollen-bearing  stamens,  and  in  most  of  which  there  are 
two-lipped  flowers  and  opposite  leaves,  though  the  latter  char- 
acter is  by  no  means  universal. 

Toad-flaxes.  The  toad-flaxes  are  recognized  at  once  by  their 
snapdragon-shaped  yellow  or  blue  flowers,  provided  with  a 
spur  like  that  of  a  larkspur  flower.  The  common  toad-flax 
of  roadsides  and  fields  blooms  in  the  summer  and  autumn. 


Minnesota  Plant  Life. 


381 


The  flowers  are  yellow  and  are  arranged  in  a  <len-e  raceme  at 
the  end  of  the  slender  stein,  not  usually  more  than  a  foot  in 
height.  The  leaves  in  this  variety  are  linear.  The  Canada 
toad-flax,  not  an  abundant  plant  in  Minnesota,  rf^-mbles  the 
ordinary  sort  except  in  the  color  of  its  flowers,  which  are  bluish 
or  white. 

Pileworts,  turtle-heads  and  snapdragons.  The  figwort  or 
pilewort  is  a  tall  herb,  often  five  or  six  feet  high,  with  a  large 
terminal  panicle  of  small  purplish,  two-lipped  flowers  of  curious 
shape.  There  are  five  stamens,  but  only  four  of  them  produce 
pollen  sacs.  The  fifth  is  reduced  to  a  little  scale.  The  stems 
are  somewhat  four-sided,  but  the  plant  has  the  typical  figwort 

capsule,with  two  chambers,  open- 
ing along  the  partitions.  The 
turtle-head  is  a  swamp  plant, 
with  white  or  pink  flowers,  large 
in  size  and  borne  in  the  axils  of 
the  upper  leaves,  or  in  terminal 
spikes.  The  flower  is  shaped 
somewhat  like  a  turtle's  head, 
hence  the  common  name.  The 
seeds  in  this  variety  are  provided 
with  wings.  The  snapdragons, 
known  also  as  beardtongues,  and 
the  monkeyflowers  have  usually 
bell-shaped  or  mouth-shaped 

Fio.182.   Monkey  flower.  After  Bntton    flowers.     Several  different  kinds 
and  Brown.  of  beard-tongues  occur  and  they 

are  especially  abundant  on  dry  banks  or  high  bluffs  in  the 
prairie  region  of  the  state.  The  monkeyflowers,  of  which 
there  are  two  sorts,  have  the  flowers  on  distinct  stems  in  the 
axils  of  the  leaves.  Each  flower  seems  to  have  an  upper  and 
lower  jaw,  closed  together  like  a  mouth.  One  variety  has  blue 
flowers  and  the  other  has  yellow.  Both  are  found  in  swamps 
or  along  streams,— not,  however,  in  peat-bogs  or  tamarack 
swamps,  or  only  very  sparingly. 

Hedge-hyssops.  The  hedge-hyssops  are  mint-like  in  their 
appearance,  but  lack  the  fragrance  of  the  mint.  There  are  two 
or  three  varieties,  one  of  which  occurs  in  peat-bogs.  The 
flowers  are  considerably  smaller  than  those  of  the  turtle-head, 


382 


Minnesota  Plant  Life. 


beardtongue  or  monkeyflower,  but  have  a  strongly  two-lipped 
aspect.  There  are  four  stamens,  in  one  variety  all  pollen-bear- 
ing, and  in  the  others  only  two  with  pollen. 

Speedwells.  The  speedwells,  of  which  there  are  several 
species,  have  only  two  stamens.  They  are  usually  provided 
with  capsules  of  a  heart  shape,  caused  by  the  deep  lobing  of 
the  typical  figwort  fruit.  Many  of  them  are  found  in  wet 
places  along  the  muddy  shores  of  ponds  or  in  woods.  One 
of  them  is  a  tall  herb,  often  six  feet  in  height,  with  willow- 
shaped  leaves  in  whorls  of  from  three  to  nine,  and  several  dense, 
spike-like  racemes  of  flowers,  the  central  one  of  which  develops 
first.  The  flowers  are  small, 
and  white  or  blue.  In  this 
variety  the  capsule  is  not 
heart-shaped.  The  plant  is 
common  in  the  edges  of 
woods. 

Gerardias.  The  Gerar- 
dias,  with  about  ten  Minne- 
sota species,  are  abundant 
in  various  localities,  but  are 
most  often  found  among 
sedges  along  the  shores  of 
lakes  or  on  dry  prairies. 
The  flowers  are  not  dis- 
tinctly two-lipped,  but  are 
almost  bell-shaped,  usually 
of  a  pink  color,  varying 
towards  violet,  purple  or  yellow.  The  leaves  are  commonly  lin- 
ear, or  at  most  lance-shaped.  The  showy  flowers,  slender  leaves 
and  capsules  of  the  figwort  type,  half  inclosed  in  the  calyx,  or 
almost  surrounded  by  it,  will  serve  to  distinguish  these  plants. 

Indian  pinks.  The  Indian  pinks,  or  painted-cups,  form  their 
two-lipped  flowers  in  leafy  spikes.  Many  of  the  leaves  in  each 
spike  are  themselves  colored  scarlet  or  yellow,  giving  to  the 
whole  structure  a  much  more  ornate  appearance  than  would  be 
produced  by  the  flowers  alone.  One  painted-cup  has  scarlet 
leaves ;  another  has  yellow  leaves,  while  yet  another  is  supplied 
with  green  leaves  to  accompany  the  flowers. 


FIG.  183.    I^ousewort.     After  Britton  and  Brown. 


Minnesota  Plant  Life. 


383 


Cow-wheats.  The  cow-wheats,  louseworts,  yellow-rattles  and 
eyebrights  are  remarkable  for  their  partial  parasitism  upon 
neighboring  plants.  If  a  turf  containing  one  of  these  varieties 
is  dug  up  and  the  earth  very  carefully  removed  by  washing,  it 
will  be  found  that  the  rootlets  of  the  figwort  attach  themselves 
to  those  of  neighboring  plants  and  in  this  way  extract  food 
material  from  the  bodies  of  their  hosts.  Such  plants  are  called 
root-parasites.  The  dependent  habit  of  these  root-parasites 
is  not,  however,  so  thoroughly  fixed  that  they  derive  the 
principal  part  of  their  nutriment  in  such  an  irregular  manner 

They  are  all  of  them  green 
plants  with  well  developed 
leaves.  The  flowers  are  two- 
lipped,  have  strongly  con- 
vex upper  lips,  and  are  of 
various  colors — white  in  the 
cow-wheat,  yellow  in  the 
rattlebox,  cream  colored  in 
the  louseworts,  and  lilac  or 
purplish  in  the  eyebright. 

Catalpa  trees.  One  tree 
related  to  the  figworts,  and 
belonging  to  the  bignonia 
family,  is  cultivated  in  Min- 
nesota, especially  in  the 
southern  part  of  the  state. 
This  is  the  catalpa,  a  very 

FIG.  184.    Bladderwort.     After  Britton  and  Brown,     beautiful       trCC     with       large 

leaves  shaped  somewhat  like  those  of  the  linden  and  handsome 
purple-mottled,  bell-shaped,  two-lipped  flowers,  produced  in 
loose  clusters.  The  pods  when  full-grown  are  a  foot  or  more  in 
length,  cylindrical  and  slender.  In  every  pod  a  large  number 
of  winged  seeds  are  matured  and  the  wings  stand  out  on  each 
side  of  the  seed  like  the  wings  of  a  bird.  Catalpa  seeds  have 
their  center  of  gravity  very  nicely  balanced  between  the  wings, 
so  that  they  lie  flat  in  the  air,  and  if  there  is  a  current  of  wind 
they  soar  in  circles  like  hawks,  and  are  often  carried  to  great 
distances. 


384  Minnesota  Plant  Life. 

Bladderworts.  Relatives  of  the  figworts  are  certain  very 
extraordinary  aquatic  plants  known  as  bladderworts.  In  Min- 
nesota all  the  forms  live  in  the  water,  except  a  little  plant  called 
the  butterwort,  which  grows  upon  rocks  along  the  north  shore 
of  Lake  Superior.  In  the  tropics,  however,  a  number  of  blad- 
derworts grow  as  perching  plants  upon  tree  trunks.  For  the 
most  part,  true  bladderworts  have  no  roots,  but  extend  in  the 
water  their  much-branched,  floating  body,  from  which  slender 
stalks  arise,  bearing  yellow,  snapdragon-shaped  flowers.  The 
leaves  of  these  plants  are  decidedly  compound  and  consist  of 
thread-like  divisions,  upon  which  are  produced,  usually  in  large 
numbers,  little,  clear,  flattened,  shrimp-shaped  bladders.  Each 
bladder  contains  generally  a  bubble  of  gas  along  with  some 
liquid,  and  by  aid  of  the  bubbles  the  plants  are  enabled  to  float 
free  in  the  water.  Being  surrounded  by  liquid,  they  have  little 
need  of  roots,  and  have  therefore  abandoned  them.  The  blad- 
ders are  not,  however,  employed  solely  as  floats,  but  each  one 
has  an  aperture,  guarded  by  a  trapdoor,  which  opens  inward 
but  not  outward.  Small  aquatic  insects  find  their  way  into 
these  bladders,  but  cannot  escape,  since  the  door  of  the  bladder 
cannot  be  opened  from  within.  Digestive  glands  are  present 
on  the  inner  surface  of  the  bladders,  and  the  bodies  of  the  little 
animals  are  used  by  the  plant  as  part  of  its  nutriment.  Blad- 
derwort  stems  resemble  somewhat  those  of  the  water-milfoils, 
but  the  latter  are  not  free  floating  plants  and  are  attached  to 
the  bottom,  nor  have  they  the  remarkable  shrimp-shaped  blad- 
ders on  their  leaves.  Bladderworts  in  flower  are  immediately 
recognized,  for  no  other  free-swimming  plants  produce  two- 
lipped  flowers.  Each  corolla  is  provided  with  a  spur  like  that 
of  the  toad-flax  flower  and  is  visited  by  insects  which  effect 
pollination.  The  fruiting  capsule  is  like  that  of  the  figworts, 
with  numerous  small  seeds.  In  Minnesota  there  occur  five  va- 
rieties of  bladderworts — to  be  discriminated  by  minute  differ- 
ences in  the  flowers,  leaves  and  bladders. 

Butterworts.  A  close  cousin  to  the  bladderworts  is  a  curi- 
ous little  plant  known  as  the  butterwort.  It  grows  in  the 
crevices  of  rocks  along  the  north  shore  of  Lake  Superior,  reach- 
ing in  such  stations  a  height  of  three  or  four  inches.  The 
leaves  are  oblong,  clustered  at  the  base  of  an  erect  axis  that 


Minnesota  Plant  Life. 


385 


bears  a  single  nodding,  two-lipped  violet  flower.  Each  leaf 
has  a  greasy  feeling  and  is  provided  with  a  viscid  secretion  in 
which  insects  are  caught.  In  the  greasy  substance  digestive 
ferments  are  elaborated,  and  by  means  of  these  the  bodies  of 
the  insects  are  converted  into  food  for  the  plant.  Through 
the  rennet-like  ferments  secreted  by  their  leaves  butterworts, 


FIG.  185.     Cancerroot.     After  Jellett  in  Afee/iati's  Monthly. 

if  placed  in  it,  will  curdle  milk.  They  are  actually  thus  em- 
ployed in  the  domestic  cheese-making  of  Lapland  and  north- 
ern Scandinavia. 

Cancerroots,     The  broom-rapes,  including  plants  known  as 

cancerroots,  beechdrops  and  squawroots,  are  represented    in 

Minnesota  by  three,  and  probably  more  species.     They  may 

be  regarded  as  derived  from  the  cow-wheats  and  louseworts, 

26 


386 


Minnesota  Plant  Life. 


just  as  were  the  dodders  from  the  morning-glories.     They  are 
strongly  parasitic  by  their  roots  and  have  lost  their  green  color, 
becoming  whitish  or  pale  like  the  Indian-pipes  or  corpse-plants. 
They  have  not,  however,  the  dead  white  color  of  the  corpse- 
plant,  and  their  flowers  are  bent  in  the  middle  and  are,  in  one 
variety,  slightly  two-lipped,  and  in  the  other  two,  strongly.     The 
one-flowered  cancerroot  sends  up  several  slender,  erect  stems, 
from  three  to  eight  inches  high,  at  the  end  of  each  of  which 
a  single  whitish-violet  flower  is  borne.     A  few  little  scales  of 
a  pale  color  appear  at  the  base  of  the  flowering  axis.     The  stem 
of  the  plant  is  subterranean  and  sends  out  a  number  of  roots 
which  attach  themselves  to  the 
roots  of  neighboring  plants.    The 
clustered   cancerroot   pushes    its 
main   stem    out   of   the    ground 
from  two  to  four  inches.     On  this 
several  single-flowered  axes  are 
developed.     The  flowers  in  both 
varieties   are   about   an   inch   in 
length.      A    third    species,    the 
Louisiana   broom-rape,   may   be 
recognized  by  the  production  of 
numerous  short-stemmed  flowers 
in  a  terminal  spike,  upon  which 
also   several    scaly   leaves    arise. 
The  whole  plant  stands  up  from 
four  to  eight  inches  in   height. 
The  flowers  are  purplish,  and  the  stems  and  scales  are  of  a  pale, 
yellowish-green  color. 

Lopseeds.  The  lopseed  family  is  represented  in  Minnesota 
by  its  only  species,  a  plant  with  the  general  aspect  of  a  nettle, 
but  bearing  two-lipped  flowers  in  slender  spikes  from  three  to 
six  inches  long  towards  the  tip  of  the  plant.  After  the  flowers 
have  been  pollinated  they  turn  downward  and  lie  flat  against 
the  axis  upon  which  they  were  borne,  giving  a  curious  barbed 
appearance  to  the  spike.  From  this  habit  the  name  "lopseed" 
is  given. 

Plantains.  The  thirty-second  order  includes  but  a  single 
family,  that  of  the  plantains,  one  variety  of  which  is  a  common 


FIG.  186.     Rugel's  plantain.     After  Brit- 
ton  and  Brown. 


Minnesota  Plant  Life. 

and  troublesome  weed  in  lawns  throughout  the  state.  The 
stems  of  the  plantains  are  very  short,  situated  underground, 
commonly  in  an  erect  position.  A  cluster  of  leaves  with  prom- 
inent longitudinal  veins  are  borne  on  this  short  stem  and  fn.m 
the  center  of  the  tufts  of  leaves  an  axis  arises,  in  the  plantains 
proper  prolonged  into  a  dense  spike  of  flowers.  In  the  related 
shoreweed,  not  known  to  occur  in  Minnesota,  the  flowers  are 
solitary  on  the  erect  axes.  Each  plantain  flower  is  provided 
with  a  four-lobed  corolla  and  calyx  and  there  are  ordinarily 
four  stamens,  though  the  number  in  some  species  is  reduced 
to  two.  The  fruit-rudiment  matures  into  a  two-chambered 
capsule  that  splits  by  a  circular  cleft,  thus  removing  the  tip 
as  a  lid  and  allowing  the  seeds  to  escape. 

In  Minnesota  there  are  six  or  seven  varieties  of  plantain. 
The  common  plantain  of  dooryards  has  broad,  smooth  or 
slightly  hairy  leaves,  arising  from  a  thick,  short  rootstock. 
The  spikes  are  long,  slender  and  many-flowered.  The  pod 
opens  by  a  ring  around  the  middle.  Rugel's  plantain  resembles 
this  closely,  but  has  fewer  flowers  in  a  spike  and  the  pods  split 
below  the  middle,  so  that  the  lid  is  the  larger  portion.  The 
rib-grass,  or  rib  plantain,  is  introduced  from  Europe  and  is 
recognized  by  its  slightly  hairy,  lance-shaped,  or  broadly  grass- 
like  leaves,  and  its  pod  splits  at  about  the  middle.  The  salt- 
marsh  plantain,  known  from  the  saline  soils  of  the  Red  river 
valley,  has  oblong,  lance-shaped  leaves  and  pods  splitting  below 
the  middle.  The  heart-leafed  plantain  has  broad,  heart-shaped 
leaves  of  a  purplish-green  color  with  smooth  surfaces.  The 
spike  is  not  continuous  but  is  interrupted  by  short,  flowerless 
areas.  The  pod  splits  at  about  the  middle.  The  woolly  plan- 
tain, found  on  prairies  in  the  Minnesota  valley,  especially 
upon  high  knolls,  has  silky  or  woolly,  very  slender  grass-like 
leaves.  The  whole  plant,  from  the  hairs,  has  a  white  aspect. 
The  pods  split  at  about  the  middle.  The  bracted  plantain  lias 
grass-like  leaves,  but  is  not  furnished  with  silky  hairs  and  the 
spike  is  clothed  with  slender  green  bracts  or  scales  which  pro- 
trude considerably  beyond  the  ends  of  the  flowers.  The  p«»d 
splits  below  the  middle. 


Chapter  XXXVIII. 

From  Bedstraws  to  Lobelias. 


The  thirty-third  order  includes  the  madder  family,  to  which 
the  exotic  coffee  and  cinchona  plants  belong.  From  the  latter 
quinine  is  manufactured.  The  Minnesota  species  are  all  herbs 
but  one — the  button-bush — and  include  about  ten  kinds  of 
bedstraw,  the  partridgeberry  and  two  Houstonias.  In  addition 
to  the  madders,  the  thirty-third  order  includes  the  honeysuckle 
family,  with  the  honeysuckles,  twinflowers,  snow-berries,  high 
bush  cranberries,  arrowwoods,  elders  and  horse-gentians;  the 
adoxa  family,  with  a  single  small  herb  known  as  the  musk  crow- 
foot or  moschatel;  and  the  valerian  family,  with  two  valerians 
and  two  lamb-lettuces.  The  teazel  family,  to  which  the  fuller' s- 
teazel  belongs,  is  not  represented  in  Minnesota. 

Bedstraws.  Of  the  madder  family  the  little  bedstraws  of  the 
woods  are  well-known  forms.  Their  stems  are  four-sided,  their 
leaves  are  apparently  in  whorls  and  are  mostly  slender  or  wil- 
low-shaped. The  stems  are  armed  with  recurved  barbs,  so  that 
they  cling  to  one's  clothing.  The  flowers  are  small,  white  and 
clustered  in  flat-topped  cymes,  often  aggregated  in  com- 
pound panicles.  Each  flower  exhibits  a  four-lobed  calyx  and 
a  four-lobed  corolla,  upon  which  four  stamens  are  borne  in 
the  notches.  The  fruit  consists  of  two  nutlets,  side  by  side, 
and  in  each  of  them  a  single  seed  is  formed.  The  different 
kinds  of  bedstraw  are  distinguished  by  the  character  of  the 
nutlets,  the  color  of  the  flowers,  and  a  number  of  minute  pecul- 
iarities which  can  scarcely  be  recognized  without  the  use  of  a 
microscope.  Most  of  the  Minnesota  varieties  have  fruits  pro- 
vided writh  hooks,  but  in  some  the  fruits  are  quite  smooth. 
The  slender,  trailing,  clinging  stem,  whorled  leaves,  four-lobed 
flowers  and  two-nutleted  fruits  will  serve  to  identify  these 
plants.  One  variety  is  a  common  prairie  flower. 


Minnesota  Plant  Life. 


389 


Partridgeberries.  The  partridgeberry  is  a  slender,  creeping 
evergreen  plant  with  opposite  leaves.  It  is  easily  mistaken  for 
a  heath,  from  which  it  must 
be  distinguished  by  its  white, 
sessile,  four-lobed  flowers,  each 
with  four  stamens  and  four- 
lobed  stigmas.  The  flowers  are 
borne  in  pairs  at  the  ends  of 
the  stems.  The  fruit  is  a  berry- 
like  body,  red  in  color,  and  con- 
sistingof  two  fused  stone-fruits, 
in  each  of  which  there  are 
four  seeds.  In  fruit  this  plant 
is  easily  mistaken  for  a  cran- 
berry; but  the  berries,  while 
edible,  have  a  flavor  different 
from  that  of  true  cranberries. 

Button-bushes.      The    but- 
ton-bush   is    a    Shrub    With    Op-    FiG.187.    Bedstraw.    After  Britton  and  Brown. 

posite  leaves  of  the  familiar  plum-leaf  shape  and  with  spher- 
ical heads  of  white  flowers.     The  cluster  of  flowers  is  about 

an  inch  in  diameter 
and  all  over  its  surface 
the  slender  stigma-stalks 
of  the  pistils  protrude  like 
so  many  short  threads. 
The  flowers  themselves 
are  crowded  together 
very  tightly,  but  upon  be- 
ing removed  show  the 
four-lobed  corolla  and  ca- 
lyx of  the  madder  family. 
This  plant  is  found  in 
the  St.  Croix  valley  and 
along  the  Mississippi,  be- 
low the  confluence  of  the 

FIG.  188.     Partridgeberry.     After  Britton  and  Brown.       ~        Croi\ 

Bluets.     The  Houstonias,  or  bluets,  are  erect  herbs  with  op- 
posite leaves,  usually  tufted,  and  not  over  ten  inches  in  height. 


390 


Minnesota  Plant  Life. 


The  flowers  are  funnel-shaped  with  the  four  calyx  and  corolla 
lobes  and  the  four  stamens  of  their  family,  but  the  stigma  is 
two-lobed.  The  flowers  are  blue  or  lilac  or  almost  white,  and 
are  arranged  in  flat-topped  clusters.  The  fruit  is  an  almost 
spherical  capsule.  The  fringed  Houstonia  has  a  fringe  of  hairs 
along  the  margins  of  the  leaves,  while  the  long-leaved  Houstonia 
has  none. 

Elder-bushes,  The  honeysuckle  family  comprises  a  group 
of  shrubs,  vines  and  herbs,  with  opposite  leaves  and  tubular, 
generally  five-parted,  flowers,  the  calyx  of  each  of  which  adheres 

to  the  surface  of  the 
fruit-rudiment,  so  that 
the  corolla  tube  and 
the  calyx  seem  to 
spring  from  the  top  of 
the  undeveloped  fruit. 
Here  are  included  the 
elders,  of  which  there 
are  two  varieties  in 
Minnesota,  the  one 
forming  a  flat-topped 
cluster  of  flowers  from 
each  of  which  a  purple 
or  black  stone-fruit  is 
produced,  and  the 
other,  panicle-clusters 
and  stone-fruits  of  a 
scarlet  or  red  color 
when  ripe.  The  berries 
of  both  varieties  are  edible.  The  leaves  are  compound  like 
those  of  the  ash,  and  when  bruised  have  a  curious  strong  smell. 
Elder  flowers  have  five-lobed  corollas  with  five  stamens,  each 
placed  in  a  notch. 

Black  haws  and  high  bush  cranberries.  Related  to  the  elders 
are  the  bushes  known  as  black  haws,  sheepberries,  arrowwoods, 
high  bush  cranberries,  or  Viburnums.  There  are  seven  or  eight 
varieties  in  Minnesota.  The  high  bush  cranberry  is  a  shrub, 
eight  to  twelve  feet  in  height,  with  opposite  leaves  shaped  some- 
what like  those  of  the  maple.  The  white,  honeysuckle-like 


FIG.  189.     High  bush  cranberry.     After  Britton  and 
Brown. 


Minnesota  Plant  Life.  391 

flowers  are  produced  in  more  or  less  flat-topped  clusters,  and 
each  one  matures  into  a  stone-fruit  with  much  the  flavor  and 
appearance  of  the  cranberry.  The  maple-leafed  arrowwood  has 
the  same  maple-shaped  leaves  seen  in  the  high  bush  cran- 
berry, but  the  stone-fruits  are  nearly  spherical  and  black. 
This  variety  does  not  grow  more  than  six  feet  high.  The 
downy-leafed  arrowwood,  with  elm-shaped  leaves,  has  black, 
oblong  stone-fruits.  Another  sort,  very  similar  in  the  foliage, 
has  almost  spherical  fruits  of  a  dark  blue  color.  Both  these 
arrowwoods  have  coarsely  notched  leaves.  The  withe-rods  and 
sheepberry  Viburnums  have  plum-shaped  leaves  with  fine  teeth 
along  the  edge.  In  the  withe-rod  the  fruits  are  of  a  pink  or 
blue  color  and  the  stone  is  round,  or  slightly  flattened.  In  the 
sheepberry  the  fruits  are  blue  or  black,  with  flat  disk-like  stones. 

These  various  Viburnums  are  found  in  moist  woods  or 
swamps.  Some  of  them,  like  the  sheepberry,  the  downy  arrow- 
wood  and  the  high  bush  cranberry,  are  not  uncommon  through- 
out the  state,  especially  toward  the  north.  The  others  are  rarer 
or  local  in  their  distribution. 

Horse-gentians.      The  horse-gentian,  or  feverwort,  is  a  com- 
mon herb  in  rich  woodland,  especially  throughout  the  southern 
and  central  portions  of    the  state.     The  leaves  are  opposite, 
entire  and  in  most  instances  blended  by  their  bases  around  th< 
stem,  so  that  the  stem  seems  to  grow  through  the  leaves, 
flowers  arise  in  the  axils  and  are  of  a  purplish  hue. 
fruits  are  orange-red,  hairy,  and  have  three  nutlets. 

Twinflowers.     The  twinflower,  not  uncommon  through 
the  wooded  portion  of  the  state,  grows  among  moss  and  might 
be  mistaken  for  the  partridgeberry.     The  slender  branches  trail 
over  the  ground,  producing  small  opposite  leaves,  and 
sional  side  stems,  at  the  ends  of  which  pairs  of  nodding  flowers 
are  borne.     The  flowers  of  the  partridgeberry  are  erect  a 
four-parted,  but  those  of  the  twinflower  are  five-parted, 
are  usually,  however,  but  four  stamens.     The  fruit  is  nearly 
spherical,  with  a  single  ripened  seed. 

Snowberries.     The  snowberries  are  little  shrubs  not  ovei 
feet  high,  and  in  one  variety  rarely  over  six  inches.     They  have 
white   berry-like  fruits  produced  in  clusters  in  the  axils  of  t 
leaves,  except  in  one  species  in  which  the  berry  is  red. 


392 


Minnesota  Plant  Life. 


leaves  are  ovate,  smooth-margined,  opposite  and  honeysuckle- 
like.  The  flowers  are  small,  with  four  or  five  teeth  to  the  corolla 
and  the  fruits  have  two  seeds  each.  The  different  varieties  may 
be  recognized  as  follows :  The  red-berried  form,  known  also 
as  the  Indian  currant,  is  at  once  distinguished  by  the  color  of 
its  fruit.  Of  the  three  with  white  fruits  the  wolfberry  protrudes 
its  stamens  and  stigma-stalks  slightly  from  the  flower,  while  the 
other  two  do  not.  Of  the  latter,  the  snowberry  is  an  erect 
shrub  one  to  four  feet  in  height,  while  the  low  snowberry 
branches  diffusely  and  averages  from  six  to  ten  inches.  All 
four  varieties  are  to 
be  found  in  the 
edges  of  woods, 
along  lake  shores 
and  in  rocky  places. 
Honeysuckles. 
Of  the  honeysuckles, 
some  are  climbing 
vines  while  others 
are  spreading 
shrubs.  The  flowers 
are  produced  in  lit- 
tle spikes  and  are 
themselves  generally 
large  and  conspicu- 
ous. The  hairy 
honeysuckle^  the 
smooth  honeysuckle, 
Sullivant's  honeysuckle,  and  the  yellow  honeysuckle,  all  have  the 
leaves  near  the  flower  clusters  grown  together  by  their  bases 
around  the  stem.  Those  just  mentioned  are  vines.  The  blue 
honeysuckle,  the  swamp-honeysuckle,  the  fly-honeysuckle  and 
the  involucred  honeysuckle  are  shrubs,  varying  in  the  different 
species  from  one  to  ten  feet  in  height.  The  hairy  honeysuckle 
is  known  by  its  hairy  leaves.  The  smooth-leafed  honeysuckle 
has  red  berries.  Sullivant's  honeysuckle  has  yellow  berries  and 
yellowish-green  flowers.  The  yellow  honeysuckle  has  bright 
orange-yellow  flowers,  that  are  sweet-scented.  The  blue  or 
mountain-honeysuckle  is  a  shrub  one  to  three  feet  in  height, 


FIG.  190.    Snowberry.     After  Brittoii  and  Brown. 


Minnesota  Plant  Life.  393 

with  oblong  leaves,  pairs  of  yellow  flowers  and  bluish-black 
berries.  The  swamp-honeysuckle  has  red  or  crimson  berries. 
The  fly-honeysuckle  has  bright  red  berries,  and  the  involucrcd 
honeysuckle,  with  yellow  flowers  and  black  berries,  may  be 
distinguished  by  the  production  of  bractlets  surrounding  the 
fruit. 

The  bush-honeysuckle  has  the  flowers  and  general  foliage  of 
the  true  honeysuckles,  but  the  fruit  is  a  capsule,  not  a  berry. 
The  Minnesota  species  is  a  shrub  from  two  to  four  feet  in  height, 
with  plum-shaped  leaves  the  margins  of  which  are  finely 
notched.  The  flowers  are  yellow,  produced  on  stalked  umbels 
in  the  axils  of  the  upper  leaves.  This  plant  is  very  abundant 
in  open  pine  woods  throughout  the  state. 

Moschatels.  The  Ado.va,  or  moschatel,  otherwise  known  as 
musk  crowfoot,  is  a  little  herb  with  the  appearance  of  a  small 
anemone.  It  is  not  more  than  six  inches  high.  The  leaves  are 
compounded  on  the  plan  of  three,  each  of  the  three  leaflets  being 
again  compounded  or  deeply  lobed.  Three  or  four  leaves  of 
this  sort  are  borne  at  the  base  of  the  flowering  axis — which  is 
slender  and  erect,  carrying  a  pair  of  three-parted  leaves  oppo- 
site each  other  and  a  little  above  the  middle.  At  the  end  of  the 
flowering  axis  is  a  small  head  of  from  three  to  six  flowers,  all 
of  them  five-parted  with  a  forked  stamen  produced  in  each 
notch.  The  fruit  is  a  green  stone-fruit,  with  from  three  to  five 
nutlets.  This  little  plant,  the  only  one  of  its  family,  has  been 
found  in  Winona  and  Goodhue  counties.  It  is  to  be  sought 
among  the  rocks  in  dark  ravines  and  is  an  arctic-American  form, 
reaching  its  southern  limit  in  Minnesota  and  northern  Iowa. 

Valerians.  The  valerian  family  includes  four  Minnesota 
species,  two  valerians  and  two  lamb-lettuces  or  corn-salads. 
They  are  strong-smelling  herbs  with  the  characteristic  odor  of 
the  drug  valerian.  The  two  species,  known  respectively  as 
tobacco-root  and  swamp  valerian,  have  pinnately  divided  leaves, 
with  slender  leaflets,  and  erect  stems  from  one  to  four  feet  in 
height,  bearing  panicles  of  tubular  flowers  with  opposite  bracts. 
The  calyx  is  fused  with  the  fruit-rudiment  and  consists  of  from 
five  to  fifteen  bristly  teeth,  which  stand  out  like  little  feathers 
around  the  mature  fruit.  The  fruit  has  but  one  chamber  and 
is  strongly  ribbed.  In  the  tobacco-root  the  flowers  are  of  a 


Minnesota  Plant  Life. 

yellowish-white  color  and  are  often  separated.  The  root  of 
this  plant  is  edible.  The  swamp  valerian  has  flowers  of  a  pink 
or  whitish  color  and  the  stem-leaves  consist  of  a  larger  number 
of  leaflets  than  in  the  tobacco-root.  Valerian  flowers  are,  in 
structure,  very  similar  to  those  of  honeysuckles,  from  which 
they  can  be  known  by  their  slight  irregularity  and  by  their 
stamens,  from  one  to  four  in  number.  The  fruit  also  contains 
but  a  single  seed  and  is  not,  as  in  honeysuckles,  a  stone-fruit 
with  pulpy  exterior. 

The  two  corn-salads  are  rather  low  herbs,  from  one  to  two 
feet  in  height,  with  opposite,  smooth-margined  leaves  and  small 
flowers,  clustered  in  heads  that  are  loosely  arranged  on  the 
forked,  flat  top  of  the  main  axis.  The  fruits  are  somewhat 
triangular  in  outline,  smooth  and  enclosed  by  the  calyx,  grow- 
ing closely  around'  the  fruit-rudiment.  There  are  three  sta- 
mens and  the  stigma  is  three-lobed.  These  plants  can  be  dis- 
tinguished from  members  of  the  honeysuckle  family  by  the 
number  of  their  stamens,  and  from  the  valerians  by  the  absence 
of  feathery  appendages  on  the  top  of  the  fruit. 

The  thirty-fourth  and  highest  order  of  plants  comprises  the 
gourd  family,  to  which  belong  such  common  garden  plants  as 
melons,  citrons,  cucumbers,  squashes,  pumpkins  and  bottle- 
gourds.  Only  two  varieties,  the  wild  cucumber  and  the  star- 
cucumber,  are  native  to  Minnesota.  In  this  thirty-fourth  order 
are  grouped  also  the  bluebells  and  lobelias,  three  small  families 
not  represented  in  the  United  States  by  native  species,  and  the 
large  and  important  sunflower  family,  to  which  a  great  variety 
of  herbs  known  as  "Composites"  belong.  The  three  Minnesota 
families  of  the  thirty-fourth  order  are  known  by  the  fusion,  or 
close  approximation  to  each  other,  of  their  stamens.  In  the 
gourd  family  the  flowers  are  for  the  most  part  regular — as  they 
are  also  in  the  bluebells.  In  the  lobelias  the  flowers  are  strongly 
two-lipped,  reminding  one  of  mint  or  snapdragon  flowers,  while 
in  the  sunflower  family  the  flowers  are  always  aggregated  in 
dense,  flat-topped,  spherical  or  cylindrical  heads  and  are  either 
all  tubular  like  honeysuckle  flowers,  all  two-sided  and  strap- 
shaped  like  dandelion  flowers,  or  partly  tubular  and  partly  strap- 
shaped  in  the  same  head,  as  is  the  case  in  sunflowers.  In  the 
latter  instance  the  tubular  flowers  are  centrally  disposed  in  the 


Minnesota  Plant  Life. 


395 


head,  while  the  strap-shaped  flowers  form  one  or  more  marginal 
rows  and  are  then  called  ray-flowers,  because  they  radiate  from 
the  center  of  the  disk. 

Gourds  and  cucumbers.  The  plants  of  the  gourd  family  are 
almost  always  provided  with  tendrils  by  which  they  climb,  and 
they  belong  to  the  highest  group  of  climbing  plants  which 
exists.  The  leaves  are  alternate  and  are  generally  large  and 
palmately  divided  like  maple  leaves.  The  calyx  is  fused  with 
the  surface  of  the  ovary  and  the  petals  arise  from  the  calyx.  The 
corolla  is  often  so  deeply  notched  that  it  is  broken  up  into  five 
separate  petals,  returning  thus  to  the  condition  of  the  flowers 
in  a  lower  series.  There 
are  from  one  to  three  sta- 
mens. The  fruit-rudiment 
is  from  one  to  three-cham- 
bered, commonly  three- 
chambered,  as  may  be  no- 
ticed on  the  dining  table 
when  sliced  cucumbers  are 
served.  The  seeds  are  for 
the  most  part  flattened  and 
contain  no  albumen.  Ex- 
tremely large  fruits  with 
great  numbers  of  seeds  are 
produced  by  some  of  the 
species  of  this  order.  The 
well-known  prize  pumpkins 
of  the  fairs,  and  the  Georgia 
watermelons  furnish  abun- 
dant proof.  Generally  the  fruits  do  not  open,  but  release  their 
seeds  by  decay  or  after  they  are  eaten  by  animals,  but  in  some 
varieties  explosive  fruits  are  known.  From  these  the  seeds  are 
ejected  as  from  a  catapult,  or  are  shot  out  into  the  air  as  from 
a  gun  or  mortar. 

The  star-cucumber  is  an  herbaceous  vine  with  palmately- 
lobed  leaves  shaped  like  those  of  the  moonseed.  The  flowers 
are  separated,  both  kinds  being  borne  on  the  same  plant.  The 
fruit  is  one-chambered  and  matures  but  a  single  seed.  Three 
or  four  of  such  fruits  are  borne  together  in  a  little  bunch  at 


FIG.  191.    Blue-bells.    After  Britton  and  Brown. 


Minnesota  Plant  Life. 


the  end  of  a  short  nodding  stem.  The  surface  of  the  fruit  is 
spiny  and  it  does  not  open  to  release  the  seeds.  This  form  of 
wild  cucumber  is  not  very  common  in  Minnesota,  but  occurs 
throughout  the  southern  part  of  the  state. 

The  wild  cucumber,  or  balsam-apple,  like  the  star-cucumber 
is  a  climbing  herbaceous  vine  with  rather  deeply  lobed  leaves, 
shaped  somewhat  like  those  of  the  hard  maple.  The  flowers 
are  separated,  both  kinds  occurring  on  the  same  plant.  The 
staminate  flowers  are  numerous  in  conspicuous  slender  racemes, 
but  the  pistillate  flowers  are  generally  solitary,  and  each  one 
ripens  an  egg-shaped  green  fruit  covered  with  weak  spines  and 
containing  from  two  to  four 
seeds,  that  are  released  by  the 
opening  of  the  fruit  at  the  end. 
The  number  of  seeds  in  the  fruit, 
the  opening  of  the  fruit,  and  its 
ordinarily  solitary  character,  will 
generally  serve  to  distinguish 
this  plant  from  the  star-cu- 
cumber. 

Bluebells.  The  bluebell  fam- 
ily includes  four  bluebells,  one 
little  herb  known  as  the  Venus' 
looking-glass,  and  six  species  of 
lobelia,  all  of  which,  except  the 
V  e  n  u  s'  looking-glass  and  the 
water  lobelia,  are  rather  common 
in  Minnesota.  The  bluebell,  or 
harebell,  is  an  abundant  plant  in 
rocky  places  and  meadows 

throughout  the  state.  Its  beautiful,  blue,  bell-shaped  flowers 
are  borne  in  a  slender  raceme,  with  several  very  narrow  bract- 
leaves  at  the  bases  of  their  stems.  The  root-leaves  of  the  plant 
are  in  most  instances  rounded,  or  heart-shaped,  but  sometimes 
all  of  the  leaves  are  slender.  A  variety  of  this  plant,  with  soli- 
tary erect  flowers  crowning  the  stems,  occurs  in  the  northeast- 
ern part  of  the  state.  The  marsh-bellflower  has  very  slender 
stems,  with  narrow  alternate  leaves,  and  the  flowers,  often 
almost  white,  are  smaller  and  paler  than  those  of  the  harebell. 
The  shape  of  the  flower  is  more  open.  The  tall,  or  wood-bell- 


FIG.  192.     Blue  lobelia.     After  Britton 
and  Brown. 


Minnesota  Plant  Life.  397 

flower,  is  a  wand  plant  of  the  woods,  varying  from  two  to  six 
feet  in  height.  The  leaves  are  lance-shaped  and  the  flowers — 
generally  of  a  brilliant  blue  color,  but  sometimes  pale  or  white 
— are  crowded  in  a  loose,  terminal  spike  with  numerous  leaves 
intermingled.  In  this  variety  the  bell-shape  of  the  flower  is 
lost  and  the  five  notches  of  the  corolla  stand  out  in  a  plane, 
making  a  wheel-shaped  flower  an  inch  or  so  in  breadth.  In 
all  these  plants  the  fruit  is  a  capsule  with  from  three  to  five 
chambers.  There  are  several  seeds,  and  the  calyx  comes  up 
over  the  fruit  or  fuses  with  the  lower  end  of  it. 

Venus'  looking-glass.  The  Venus'  looking-glass  is  known 
by  the  small,  strongly  clasping,  shell-shaped  leaves,  in  the  axils 
of  which  the  violet  or  blue  flowers  are  gathered.  The  plant  is 
uncommon  but  may  be  looked  for  in  the  edges  of  woods. 

Lobelias.  Lobelias,  as  has  been  said,  might  from  the  shape 
of  their  flowers  be  mistaken  for  mints  or  figworts.  Their  cap- 
sular  fruits  are,  however,  quite  different  from  the  four  nutlets 
which  the  mint  develops  and  the  flower  may  always  be  dis- 
tinguished from  that  of  a  figwort  or  mint  by  the  blending  with 
each  other  of  the  stamens.  One  variety  of  lobelia — rare  in 
Minnesota — is  aquatic,  commonly  rooting  in  the  mud  at  the 
border  of  lakes  or  ponds.  It  has  hollow,  quill-shaped  sub- 
merged leaves,  clustered  around  the  base  of  a  slender  stem  from 
six  to  eight  inches  in  height,  and  at  the  end  of  this  the  pale  blue 
flowers  are  gathered  in  a  loose  raceme.  The  cardinal-flower, 
or  red  lobelia,  to  be  found  in  swamps  or  rich  soil  along  the 
lowrer  Mississippi,  is  recognized  at  once  by  its  conspicuous 
scarlet  flowers,  arranged  in  a  many-flowered  raceme.  The 
leaves  are  willow-shaped  and  the  whole  plant  is  generally  over 
two  feet  in  height.  The  flowers  are  about  an  inch  long.  The 
large  blue  lobelia,  common  throughout  the  southern  part  of  the 
state,  much  resembles  the  red  lobelia,  except  that  its  flowers 
are  bright  blue.  In  both  these  varieties  white  flowers  are 
sometimes  produced.  The  pale  blue  lobelia  is  a  slender  plant 
of  dry  soil,  abundant  in  the  southern  part  of  the  state  and  rec- 
ognized by  its  smaller  flowers,  four  or  five  lines  in  length.  The 
leaves  are  rather  thick,  of  an  oblong  shape,  with  short  stems, 
but  the  stem-leaves  are  generally  sessile.  The  flowering  raceme 
is  very  long  and  slender,  reaching  a  maximum  length  of  two 


398  Minnesota  Plant  Life. 

feet  and,  commonly,  of  eight  to  fifteen  inches  from  the  tip  to 
the  lowest  flower.  The  Indian-tobacco  lobelia,  not  so  frequent 
as  some  of  the  others,  may  be  identified  by  its  broadly  plum- 
shaped,  pointed  leaves  and  its  light  blue  flowers  in  rather  loose, 
spike-like  racemes.  Kalm's  lobelia,  the  commonest  of  all  the 
varieties  in  Minnesota,  is  especially  abundant  in  peat-bogs,  on 
banks  of  lakes  and  streams  and  in  meadows.  It  is  a  slender 
plant,  with  light  blue  blossoms  in  loose,  few-flowered  racemes. 
The  flowers  are  about  the  size  of  those  of  the  pale  lobelia,  or 
rather  smaller,  but  they  are  not  exhibited  in  the  long  slender 
clusters,  characteristic  of  the  other  varieties.  The  fruit  of  the 
lobelias  is  a  capsule,  usually  with  two  chambers,  and  to  its  sur- 
face the  calyx-tube  is  closely  attached. 


Chapter  XXXIX. 

Dandelions,  Ragweeds  and  Thistles. 


The  last  and  highest  family  comprises  the  plants  known  as 
Composites.  It  includes  some  11,000  species  of  herbs  and 
shrubs,  with  a  very  few  trees,  well  distributed  over  all  regions 
of  the  world,  and  is  characterized  by  the  aggregation  of  the 
flowers  into  composite  heads.  These  heads  are  subtended  by 
groups  of  bract-leaves  to  which  is  given  the  name  of  involucre. 
The  involucre  is  a  green,  closely  packed  series  of  scales,  such 
as  may  be  seen  below  the  head  of  a  sunflower  or  thistle.  In 
some  plants,  such  as  the  burdocks  or  cockleburs,  the  involucre 
produces  bur-like,  hooked  or  barbed  groups  of  bristles,  by 
means  of  which  all  the  fruits  of  a  head  are  distributed  as  a  unit. 
There  are  two  main  series  of  composite  plants,  one  of  which 
is  distinguished  by  the  presence  of  a  milky  juice,  while  in  the 
other  no  milk  exudes  on  the  breaking  of  the  stems  or  foliage. 
Dandelions,  lettuce,  sow-thistles  and  chicory  serve  to  illustrate 
the  first  series,  while  asters,  goldenrods,  burdocks,  sunflowers, 
thistles,  cockleburs  and  ragweeds  are  examples  of  the  second. 
The  composites  with  milky  juice  develop  what  are  known  as 
strap-shaped  corollas  for  all  the  flowers  of  a  head.  Such  strap- 
shaped  corollas  may  be  conceived  to  arise  by  the  splitting  of 
a  tubular  corolla  —  like  that  of  a  honeysuckle  —  down  one  side, 
near  to  the  fruit-rudiment.  Very  often,  as  in  dandelion  flowers, 
five  little  notches  will  be  found  at  the  edge  or  tip  of  the  strap. 
These  represent  the  five  fused  petals  of  the  original  tubular 
flower.  Those  members  of  the  composite  family  which  have 
no  milky  juice  produce,  in  many  instances,  at  the  margin  of 
the  head,  the  strap-shaped  flowers  ;  but  some,  and  often  all  the 
flowers  in  a  head  are  tubular,  like  miniature  honeysuckle  flow- 
ers. The  sunflower  or  the  daisy  furnishes  an  example  of  a  head 
in  which  strap-shaped  flowers  are  produced  laterally  and  tubu- 


400 


Minnesota  Plant  Life. 


lar  flowers  centrally,  and  the  thistle  furnishes  one  in  which  all 
the  flowers  are  tubular. 

In  composite  flowers  the  stamens  generally  have  their  pollen- 
bearing    portions    fused    to- 
gether into  a  ring,  while  their 
^^^^^^^  stems    are    free.     The    fruit- 

«-   ^;  rudiment  is  composed  of  two 

*>  1«*  carpels,  with  a  single  cham- 

ber in  which  a  single  seed 
matures.  The  calyx  is  always 
fused  with  the  surface  of  the 
fruit-rudiment,  and  in  a  great 
many  varieties  the  calyx  pro- 
duces a  bristly  or  scaly  series 
of  appendages  for  distribut- 
ing the  fruits  in  air  currents. 
The  well-known  parachutes 
of  the  dandelion  are  such 
areas, with  the  margins  frayed 
out  into  circles  of  little  bris- 
tles. Sunflower  fruits  are 
provided  with  a  pair  of  scales 
similarly  derived  from  the 
calyx.  When  the  fruits  are 
enclosed  in  burs,  the  calyx 
sometimes,  as  in  the  cockle- 
burs,  develops  this  flying  ap- 
paratus but  poorly,  while  in 
other  instances,  as  in  the  bur- 
docks, flying  appendages  are 
produced  upon  each  fruit, 
probably  reminiscences  of  an 
earlier  condition  when  the 
bur-method  of  distribution 
had  not  been  perfected.  The 
modified,  aeronautic  calyx  of 

FIG.   193.     Chrysanthemum   in   flower.      After      4-Ue     r  n  m  n  O  m'  t  P     flower     k 
Miller.     Bull.   147,   Cornell  Ag.    Expt.  Sta- 

tion-  known  as  pappus. 


Minnesota  Plant  Life. 


401 


There  are  in  Minnesota  between  240  and  250  species  of 
composites,  including  the  ironweeds,  the  blazing-stars,  the  thor- 
ough worts  or  bonesets,  the  asters,  the  fleabanes  and  Boltonias, 


FIG.  194.     Dandelions  in  flower.     I<ake  Calhoun.    After  photograph  by  Hibbard. 

the  goldenrods,  the  rosimveeds  or  compass-plants,  the  cone- 
flowers,  sunflowers,  tickseeds,  bur-marigolds  or  beggar-ticks, 
sneezeweeds,  chrysanthemums,  tansies  and  yarrows,  cudweeds, 
everlastings,  ragworts,  thistles,  burdocks,  ragweeds,  cockleburs, 

27 


4<D2  Minnesota  Plant  Life. 

marsh-elders,  chicories,  hawkweeds,  rattlesnake-roots,  wild  let- 
tuces, dandelions,  sow-thistles  and  corn-flowers.  In  some  of 
these  groups  there  are  a  large  number  of  Minnesota  species. 
For  example,  there  are  six  sorts  of  blazing-stars,  six  thorough- 
worts,  nine  or  ten  fleabanes,  thirty  goldenrods  and  about  forty 
asters,  besides  eleven  or  twelve  wormwoods  or  sage-brushes, 
ten  or  eleven  thistles  and  fifteen  sunflowers. 

The  composite  family  may  for  convenience  be  divided  into 
three  sub-families,  the  dandelions,  the  ragweeds  and  the  sun- 
flowers. To  the  dandelion  family  about  thirty  Minnesota 


FIG.  195.     Dandelions  in  fruit.    After  photograph  by  Williams. 

species  belong.  The  characters  by  which  they  are  classified  are 
minute  and  it  is  not  possible  to  go  into  them  in  detail.  A  few 
of  the  common  forms  may,  however,  be  described. 

Dandelions  and  their  relatives.  The  dandelion  is  known  by 
its  broad  flat  head  of  yellow  flowers,  becoming  closed  in  the 
early  stages  of  fruiting.  In  later  stages  the  head  opens  again 
and  the  disk  of  the  flower-cluster  becomes  convex.  On  this 
the  little  spindle-shaped  nutlets  are  situated.  Above  each 
nutlet  the  calyx  is  prolonged  into  a  rigid  thread  at  the  end 
of  which  the  pappus-hairs  diverge  in  an  umbrella-shaped 
circle. 


Minnesota  Plant  Life. 


403 


The  sow-thistles  have  small,  yellow  dandelion-like  flower- 
heads,  arranged  in  panicles  or  in  flat-topped  clusters.  The 
pappus,  as  in  thistles,  stands  in  a  tuft  on  the  top  of  the  nutlet. 
The  meadow  salsify  has  flowers  and  fruits  very  much  like  those 

of  the  dandelion,  but  the  leaves  are 
all  more  grass-like  in  appearance. 
The    autumn    dandelion    has    a    few 
leaves  clustered  about  the  base  of  a 
rather  slender,  erect  stem,  at  the  end 
of    which  a  dandelion-like   flower  is 
borne.     The  fruit  is  slender  and  the 
pappus-bristles  are  brownish  in  color 
and  on  close  observation  are 
seen  to  be  like  little  feathers. 
The  dwarf  dandelion  has  gen- 
erally   two    kinds    of     pappus 
bristles,  an  outer  row  of  short 
brown    scale-like    bristles    and 
*an  inner  row  of  slender,  erect, 
stiff,  barbed  bristles.     The 
hawk's-beards,     with     flowers 
decidedly  similar  to  those  of  the  dan- 
delion, have  a  copious  pappus  of  slen- 
der bristles,  arising  in  a  spreading  tuft 
from  the  top  of  a  many-furrowed  fruit. 
The   closely   related   hawkweeds   can 
scarcely  be  distinguished  by  any  but 
very    minute    characters.      The    wild 
lettuces  look  much  like  some  of  the 
hawkweeds,  but  the  flowers  are  more 
often  blue  than  yellow.     The  prickly 
FIG.  i96.  wild  lettuce,  a  compass-  lettuce,  a  compass-plant,  may  be  dis- 

plant;  the  fruits  stand  in  heads,  .  1-1  i_-    i 

and  each  fruit  is  provided  with   tinguislied  from  the  sow-thistle,  which 
ItkCon111"  °f  briStlCS'  After  *  somewhat  resembles,  by  the  dande- 
lion-like fruits,  with  the  pappus  ele- 
vated above  the  tip  of  the  nutlet  on  a  slender  prolongation  of 
the  calyx.     Its  leaves  are  prickly,  and  those  on  the  stem  may 
twist  so  that  their  edges  point  up  and  down.     The  whole  plant 
is  generally  flattened  by  the  twisting  of  its  leaves,  and  the  ends 


404 


Minnesota  Plant  Life. 


FIG.  197.     Rattlesnake-root, 
and  Brown. 


of  the  leaves  show  a  tendency  to  point  either  north  or  south. 

One  observing  the  plant  carefully  can  easily  see  that  the  leaf- 
area  as  a  whole  exposes  its  sur- 
face toward  the  east  and  toward 
the  west.  The  blue-flowered  va- 
rieties, some  of  them  wand-plants 
from  three  to  twelve  feet  in 
height,  are  known  by  the  copious 
heads  of  small  blue  flowers  ar- 
ranged in  compound  panicles. 
They  are  common  at  the  edges  of 
woods. 

A  curious  little  flower,  known 
as  Lygodesmia,  is  a  desert  plant 
with  rigid  branching  stem  about 
a  foot  in  height,  and  with  small, 
After  Britton  awl-shaped  leaves  and  flowers  in 
pink  heads  of  from  three  to 

twelve,  giving  to  the  whole  cluster  quite  the  appearance  of  a 

small  carnation.     It  is  a  wanderer  from  the  plains  of  the  south- 
west. The  Not/iocalais  and 

its    relatives    are    prairie 

plants    with    grass-like 

leaves  and  dandelion-like 

heads.     The  rattlesnake- 
roots,    some   varieties    of 

which  are  abundant  in  the 

Minnesota  woods  and  in 

shaded    ravines,    may    be 

known  by  their  heads  of 

flowers,    nodding   in    the 

common  forms,  arranged 

in  panicles  and  of  a  pink 

or   purplish    color.     One 

of    these    with    curiously 

triangular  leaves  is  abun- 
dant in  deep  woods,  flow-" 

ering  in  autumn,  and  with 

its  mature  fruits  surmounted  by  a  deep  brown  tuft  of  pappus 

hairs. 


FIG.  198.     Cocklebur.     After  Britton  and  Brown. 


Minnesota  Plant  Life. 


405 


Ragweeds  and  cockleburs.  The  ragweed  family,  with  six 
or  seven  native  species,  includes  the  ragweeds,  cockleburs  and 
marsh-elders.  The  cocklebur,  of  which  two  varieties  occur  in 
Minnesota,  is  known  by  the  conversion  of  the  involucre  of  each 
pistillate  head  into  a  two-pronged,  many-hooked  bur  in  which 
two  fruits  are  enclosed.  A  striking  peculiarity  of  the  cockle- 
bur  is  that  one  of  its  two  fruits  will  germinate  the  first  season, 
while  the  other  ordinarily  lies  dormant  for  a  year.  The  marsh- 
elder  is,  in  Minnesota,  a  tall  roadside  weed  with  leaves  shaped 
like  those  of  the  cocklebur.  The  panicled  heads  of  green  statn- 

inate  flowers  are  intermixed 
with  small  pistillate  flowers 
without  corollas.  The  rag- 
weeds, of  which  three  species 
are  common  in  Minnesota,  are 
also  known  as  "hay-fever 
plants,"  because  their  copious 
pollen-spores  produced  in  the 
autumn  will,  if  inhaled,  some- 
times germinate  in  the  nostrils 
and  the  little  thread-like  male 
plants  will  then  irritate  the 
nasal  membranes  of  persons 
subject  to  the  disease.  The 
tall  ragweed,  which  sometimes 
grows  fifteen  feet  in  height  in 
low  ground  along  roadsides, 
has  three-divided  leaves  and 
numerous  slender  racemes  of  heads.  The  other  ragweeds  have 
pinnately  divided  or  compounded  leaves,  and  are  a  foot  or  two 

tall. 

Sunflowers  and  their  relatives.  The  sunflower  family  has 
about  200  native  species.  Here  are  classified  the  ironweeds, 
herbs  of  moist  soil  with  willow-shaped  leaves  and  purplish  small 
heads,  arranged  in  flat-topped  clusters;  also  the  thoroughworts, 
distinguished  from  the  ironweeds,  which  in  outward  appearance 
they  much  resemble,  by  the  pappus.  In  thoroughworts  this  is 
composed  of  numerous  slender  bristles,  while  in  the  ironweeds 
it  is  double,  the  inner  whorls  alone  being  constituted  of  bristles, 


FIG.  199.     Ragweed.      After    Britton     and 
Brown. 


406 


Minnesota  Plant  Life. 


while  the  outer  is  made  up  of  short  scales.  Related  to  the 
thoroughworts  are  the  blazing-stars  of  the  prairies  and  thickets, 
some  sorts  being  also  very  prominent  in  open  pine  woods. 
These  are  wand-plants,  with  handsome  pink  or  purple  heads, 
of  massive  appearance  in  ordinary  varieties,  all  arranged  in  a 
spike-like  cluster  at  the  end  of  the  upright  stem.  The  leaves 
are  very  narrow,  like  short  grass  leaves.  The  gum-plant  or 
Grindelia,  may  be  known  by  its  sticky  leaves  and  heads, — the 
latter  with  yellow  rays  and  yellow  disk  flowers. 


FIG.  200.    Autumnal  vegetation  of  marsh  border.     Thoroughwort  or  joe-pye  weed.     After 

photograph  by  Williams. 

The  goldenrods  are,  for  the  most  part,  wrand-plants  with 
densely  panicled  small  yellow  heads.  In  many  varieties  the 
heads  are  arranged  in  one-sided  racemes  and  these  are  aggre- 
gated together  in  paniculate  clusters,  in  three  varieties  becom- 
ing flat-topped.  Some  goldenrods,  found  in  prairie  districts, 
have  rather  narrow  leaves,  while  others,  natives  of  deep  woods, 
have  them  very  'broad,  ovate  or  oblong.  The  different  kinds 
of  goldenrods  may  be  known  by  the  sizes  of  the  heads,  by  the 


Minnesota  Plant  Life. 


407 


Boneset  or  thoroughwort. 
Brown. 


After  Britton  and 


arrangement  of  the  heads  in  compound  flower-clusters  and  by 

the  texture  and  shape  of  the  leaves.     Daisies  and  oxeye  daisies, 

asters  and  Boltonias  are 

kindred  to  the  golden- 
rods.  The  asters,  which 

bloom    so    abundantly 

in  the  autumn  of   the 

year,  may  be  known  by 

their  generally  purple 

or  whitish  ray-flowers, 

their   pappus,    consist- 
ing of  a  single  series  of 

hair-like    bristles,    and 

their  disk  flowers  of  a 

red,  purplish  or  brown- 
ish color.     Some  asters 

which  live  in  the  forest 

have   very   broad   and 

heart-shaped  leaves,   FlG  m 

while  others,  at  home 

in  the  open,  produce  leaves  that  are  slender  or  even  awl-shaped. 

The   flowers   are   ordinarily   arranged   in    compound   panicles 

or  flat-topped  clusters,  very 
numerous  in  some  species, 
in  others  fewer.  The  one- 
sided, racemed  inflorescence 
aggregates  of  the  golden- 
rods  are  found  in  a  few  spe- 
cies. Asters  are  to  be  dis- 
tinguished from  each  other 
by  the  same  characters  men- 
tioned for  the  goldenrods. 

Fleabanes  have  commonly 
very  slender,  thread-like  ray 
flowers,  usually  of  a  white 
color,  shading  often  into 
violet  or  purple.  The  ever- 
lastings, to  which  the  com- 
mon little  Indian  tobacco  belongs,  are  for  the  most  part  woolly 
plants  with  separated  flowers.  The  staminate  flowers  are  pro- 


FIG.    202. 


Blazing-star.      After 
Brown. 


Britton     and 


408 


Minnesota  Plant  Life. 


duced  on  one  plant  and  the  pistillate  on  another,  or  they  may 
both  arise  on  the  same  plant.  The  rosinweeds  include  three 
rather  marked  varieties,  among  which  is  the  Indian  cup,  in 


FIG.  203.  Autumnal  composite  vegetation.  In  foreground  golden-rods,  sunflowers  and 
asters;  in  background,  on  brow  of  cliff,  wormwood  or  sage-brush.  After  photograph 
by  Williams. 

which  the  bases  of  the  large  leaves  are  grown  together  around 
the  stem,  forming  deep  cups,  through  which  the  four-angled 
stem  seems  to  grow.  Water  is  caught  in  these  cups  and  they 


Minnesota  Plant  Life. 


409 


are  often  filled  with  the  dead  bodies  of  insects.  It  is  probable 
that  the  plant  is  partially  carnivorous  like  the  pitcher-plants. 
The  flowering  heads  are  yellow,  like  small  sunflowers.  The 
compass-plant  rosinweed  produces  near  the  surface  of  the 
ground  a  number  of  leaves  a  foot  or  more  long,  with  very  deep 
lobes  running  from  the  margin  to  near  the  midrib.  These 
leaves  stand  upright  and  arrange  themselves  with  their  edges 
north  and  south.  A  third  variety,  known  as  the  prairie-dock, 
displays  large,  long  heart-shaped  leaves,  a  foot  in  length  and 
six  inches  or  more  in  width  at  the  base.  They  compose  a  large, 
loose  rosette  and  do  not 
stand  erect  like  those  of  the 
compass-plant.  In  each  va- 
riety the  flower  heads  are 
yellow,  both  in  the  disks  and 
in  the  rays.  The  related 
oxeyes  or  sunflower  herbs, 
as  their  name  indicates,  re- 
semble sunflowers  closely. 

In  the  coneflowers  the 
disk  is  hemispherical,  con- 
ical or  columnar  in  contour. 
One  variety,  the  long-  i 
headed  coneflower,  has  the 
disk  flowers  arranged  in  a 
cylindrical,  pointed  cone,  of 
a  brownish  color  when  ma- 
ture, with  a  few  large  yel- 
low ray  flowers  at  the  base.  The  sunflowers  are  mostly  upright 
herbs,  with  heads  consisting  of  numerous  tubular  disk  flowers 
surrounded  by  conspicuous  yellow  rays.  The  ray  flowers  con- 
tain neither  stamens  nor  pistils  and  are  purely  for  the  purpose  of 
attracting  insects  to  the  less  ornamental  stamen-  and  carpel-bear- 
ing flowers  of  the  disk.  Such  a  division  of  labor  between  the 
different  flowers  of  the  head  marks  a  very  high  degree  of  special- 
ization. In  some  sunflowers  the  foliage  leaves  are  opposite 
while  in  others  they  are  alternate.  Some  have  sessile  leaves, 
while  in  others  they  are  stemmed.  In  some  the  foliage  is 
smooth,  while  in  others  it  is  rough,  and  in  some  the  disk 


FIG.  204.     Early  golden-rod. 
Brown. 


After  Britton  and 


Minnesota  Plant  Life. 


flowers  are  purple,  while  in  others  they  are  yellow.  The  shapes 
of  the  leaves  and  of  the  flower  heads  differ  in  the  different  kinds ; 
and  the  arrangement  of  the  flower  heads  varies  slightly,  though 
ordinarily  they  are  either  solitary  or  in  flat-topped  clusters. 
To  this  genus  of  plants  belongs  the  artichoke,  the  rootstock  of 
which  bears  tubers. 

The  tickseeds  are  little  yellow-flowered  composites,  with  the 
pappus  much  reduced,  appearing  commonly  as  a  couple  of  small 


FIG.  205.     Asters  and  golden-rod.    Banks  of  the  Mississippi.     After  photograph  by  Williams. 

teeth  at  the  end  of  the  somewhat  winged  nutlet.  The  bur- 
marigolds  produce  yellow  flower  heads,  from  the  disk  flowers 
of  which  arise  fruits  with  two  or  more  strongly  barbed  bristles 
upon  each,  for  in  these  plants  the  pappus  has  lost  its  aeronautic 
characters  and  is  adapted  to  fasten  the  fruits  to  the  bodies  of 
wandering  animals.  The  little  flattened,  pitchfork-like  seeds 
which  stick  to  one's  clothes  in  the  autumn  are  those  of  the  bur- 
marigold  or  beggar-ticks.  The  several  different  varieties  are 
known  by  the  shape  of  the  nutlets,  by  the  foliage  and  by  the 


Minnesota  Plant  Life. 


411 


flowering  heads.  One,  the  highest  type  of  aquatic  vegetation 
in  Minnesota,  is  called  the  water-marigold,  or  Beck's  marigold, 
and  is  found  in  ponds  and  brooks.  Its  submerged  leaves  are 
all  dissected  into  thread-like  lobes.  The  flowering  heads,  dis- 
tinctly composite  in  their  appearance,  are  thrust  out  of  the 
water,  and  just  below  them  a  few  willow-shaped  leaves  are  borne. 
The  nutlets  produce  from  three  to  six  barbed  bristles  and  are 
fitted  for  attachment  to  the  plumage  of  birds  or  the  fur  of 
animals. 

The  yarrow  is  an  erect  herb,  a  foot  or  two  in  height,  with 
leaves  of  strong,  tansy- 
like  odor,  dissected  pin- 
nately  into  numerous  tiny 
segments.  The  heads  are 
very  numerous,  borne  in 
dense  terminal  flat-topped 
clusters.  The  ray  flow- 
ers are  white  or  pink. 
Tansy,  a  common  herb 
escaped  from  cultivation, 
is  known  by  the  highly 
aromatic  foliage  and  the 
pinnately  divided  leaves. 
Wormwoods,  of  which 
there  are  several  sorts, 
contain  the  peculiar  bitter 
principle  used  as  a  flavor- 
ing substance  in  the  man- 
ufacture of  absinthe. 
Many  of  them  are  very 

white  or  silvery,  from  the  numerous  hoary  hairs  with  which  the 
leaves  and  stems  are  covered.  The  heads  are  small  and  aggre- 
gated in  dense  spikes,  compound  racemes  or  panicles,  and  the 
foliage  exhales  a  characteristic  aromatic  odor.  Colts'foots,  to 
be  found  in  marshes,  may  be  known  by  their  thick  horizontal 
rootstocks,  by  their  scaly  stems  on  which,  in  flat-topped  clus- 
ters, a  few  heads  are  borne,  and  by  their  large  root-leaves — in 
one  variety  palmately  divided  like  the  leaves  of  some  anemones, 
and  in  another  of  a  broadly  arrow-head  shape.  Related  to  the 


FIG.  206.     Rosinweed  compass-plant, 
and  Brown. 


After  Britton 


4I2 


Minnesota  Plant  Life. 


colts'foots  are  the  arnicas,  fireweeds  and  Indian  plantains. 
Three  varieties  of  the  latter  occur  in  Minnesota.  In  one  of 
these  the  leaves  are  similar  to  those  of  the  dooryard  plantain, 
while  the  small  flowering  heads  are  borne  in  large  flat-topped 
clusters  at  a  height  of  from  two  to  six  feet.  In  another  form 

the  leaves  are  kidney- 
shaped,  while  in  still 
another  they  are  trian- 
gular, deeply  toothed 
and  provided  with  a 
white  bloom  on  the  un- 
der side.  The  ground- 
sel, ragworts,  squaw- 
weeds  and  butterweeds 
or  Senecios,  are  rela- 
tives of  the  Indian 
plantains.  The  eight 
or  nine  varieties  which 
are  found  in  Minnesota 
have  somewhat  the  ap- 
pearance of  y  e  1 1  o  w- 
flowered  asters.  I  n 
most  of  them  there  are, 
as  in  mustards,  rosettes 
or  root-leaves  different 
in  shape  and  appear- 
ance  from  the  stem- 
leaves,  and  the  flowers 
are  commonly  borne  in 
flat-topped  clusters. 
These  plants  cannot  be 
mistaken  for  the  hawk- 
weeds  and  their  allies 
because  they  have  no 

milky  juice.  One  variety,  the  marsh  fleawort,  or  marsh 
groundsel,  is  an  abundant  swamp  plant  with  a  beautiful  flat- 
topped  cluster  of  yellow  heads  borne  on  a  very  stout,  hollow 
stem  from  six  inches  to  two  feet  in  height.  In  some  of  the 
groundsels  the  leaves  are  deeply  pinnately  divided,  while  in 


FIG.  207. 


Cone-flowers. 

Williams. 


After  photograph  by 


Minnesota  Plant  Life. 


413 


others  they  are  more  nearly  entire.  The  root-leaves  in  all 
instances,  with  perhaps  one  or  two  slight  exceptions,  differ  in 
appearance  from  the  leaves  on  the  flowering  stems  and  are  gen- 
erally larger. 

The  burdocks  are  herbs  with  very  large  ovate  leaves,  cottony 
on  the  under  side,  but  becoming  dark  green  above.  Two 
varieties  occur  in  Minnesota,  the  large  burdock  and  the  small. 
The  flowering  heads  in  each  are  surrounded  with  involucres, 
the  scales  of  which  become  hooked  at  the  end  and  barbed  so 
that  the  whole  flower  head  separates  when  in  fruit  and  is  dis- 
tributed on  the  fur  of  animals. 
The  seedlings  of  the  burdock 
spring  up,  therefore,  in  little  clus- 
ters, one  from  each  of  the  numer- 
ous enclosed  fruits.  Both  species 
are  locally  known  as  "wild  pie- 
plant" on  account  of  their  large 
leaves  like  those  of  the  rhubarb. 

Thistles  are  stout  herbs  of 
wand-like  habit,  often  ten  feet  or 
more  in  height  and  with  hand- 
some heads  made  up  of  pink  or 
purple  tubular  flowers.  The  foli- 
age and  the  involucre  is  pro- 
tected by  spines  and  the  fruits 
are  provided  with  abundant  pap- 
pus, sometimes  of  plumy  and 
sometimes  of  hair-like  bristles.  FIG.  208.  prairie  cone-flower.  After  Brit- 
Related  to  the  thistles  is  the 
bachelor's-button  or  corn-flower, 
flowers  of  a  head  are  not  strap-shaped,  but  are  overgrown 
tubular  flowers,  blue  or  purple  in  color. 

Summary  statement.  There  have  now  been  passed  in  re- 
view a  considerable  number  of  Minnesota  plants,  sufficient  to 
illustrate  all  the  important  groups.  The  lower  groups  are 
marked  by  relative  simplicity  of  structure,  increasing  in  com- 
plexity to  the  highest.  Such  plants  as  the  thistles  and  sunflow- 
ers occupy  in  the  plant  kingdom  a  position  similar  to  that  of 
man  in  the  animal  kingdom.  Structurally  they  are  the  most 


ton  and  Brown. 


In  this  variety  the  marginal 


Minnesota  Plant  Life. 


improved.  Especially  in  the 
composite  family  should  it 
be  observed  that  the  ftower 
cluster  has  become  an  area 
perfected  under  somewhat 
the  same  laws  that  were  seen 
to  govern  the  perfecting  of 
the  flower.  It  will  be  re- 
membered that  the  flower 
itself  is  supposed  to  have 
originated  from  groups  of 
leaves  arranged  on  a  slender 
axis.  As  this  axis  aban- 
doned itsstarchmaking 
work,  the  leaves  were  gath- 
ered into  a  more  compact 
structure  by  the  shortening 
of  their  general  stem.  Thus  FlG' m-  Water  bur-marisold-  After  Britton 

and  Brown. 

from  cones  like  those  of  the 

pines  arose  the  flatter  aggregates  of  spore-bearing  leaves  known 
as  "flowers"  in  the  higher  plants.    These  flowers  were  essentially 

branches  of  the  stem  and  in 
the  lower  families  such 
branches  more  commonly 
maintained  their  primitive  po- 
sition with  reference  to  each 
other,  so  that  the  flowers  were 
arranged  loosely  upon  the 
plant.  In  higher  forms  defi- 
nite flower  clusters  of  particu- 
lar shape  came  into  existence 
and  the  law  of  condensation 
finally  permitted  the  produc- 
tion of  the  flat-topped  cluster 
of  the  sunflower  in  which  hun- 
dreds of  flowers  are  gathered 
together  on  a  broad  circular 
disk.  Among  these  flowers  of 

FIG.  210.    Corn-flower.     After  Britton  and 

Brown.  the   disk   a   division   of  labor 


Minnesota  Plant  Life.  4 1  5 

arose  so  that  some  flowers  abandoned  their  stamens  and  pistils 
and  became  converted  into  neutral  ray  flowers,  useful  in  adding 
to  the  attractiveness  of  the  cluster,  thus  possibly  inducing  in- 
sects to  visit  it  more  freely.  The  heads  of  flowers  came  them- 
selves to  stand  in  definite  compound  clusters,  so  that  just  as 
there  was  a  spike  of  flowers  in  the  plantain  family  there  later 
came  to  exist  a  spike  of  flower-heads,  as  in  blazing-stars,  and 
just  as  the  flowers  of  the  high  bush  cranberry  learned  to  stand 
in  flat-topped  clusters,  so  in  the  thoroughworts  and  asters,  heads 
of  flowers  were  arranged  in  similar  inflorescences. 

Each  flower  of  the  composite  head  shows  a  high  degree  of 
fusion  between  its  parts.  That  is  to  say,  it  is  a  flower  of  high 
rank.  The  originally  separate  carpels  are  blended  in  pairs  into 
the  fruit-rudiments,  one  to  each  flower.  The  stamens  in  all 
Minnesota  genera  of  composites  except  one  are  fused.  The 
petals  of  the  corolla  are  blended  into  a  tube  which  in  some  of 
the  flowers  becomes  split,  to  make  the  strap-shaped  corolla  of 
the  dandelion  or  the  strap-shaped  ray  flower  of  the  daisy.  The 
calyx  parts  are  blended  together  into  a  calyx  tube  and  this  be- 
comes fused  with  the  surface  of  the  fruit-rudiment,  developing 
in  many  of  the  genera  a  distributing  apparatus  made  up  of 
bristles,  variously  arranged  and  of  various  structure.  The 
leaves  below  the  flowering  head,  in  such  forms  as  the  burdock 
and  cocklebur,  become  modified  to  assist  the  distribution  of  the 
seeds. 

Three  types  of  higher  plants  may  be  regarded  as  terminal, 
the  orchids  standing  at  the  top  of  the  series  of  plants  with  one 
seed  leaf,  the  dogwoods  at  the  top  of  the  lower  series  of  two 
seed-leafed  plants,  and  the  sunflowers,  dandelions  and  thistles 
at  the  top  of  the  highest  series.  Among  orchids,  the  flower 
cluster  was  not  highly  improved  as  such,  but  the  perfecting 
tendencies  worked  rather  toward  the  production  of  a  much 
complicated  floral  mechanism,  irregular  in  shape,  reflecting  the 
strong  influence  of  those  forces  which  develop  bilateral  sym- 
metry, and  very  exact  in  its  adjustment  to  the  habits  of  the 
insects  which  co-operated  in  its  pollination.  The  clusters  of  the 
dogwood,  although  not  so  fully  perfected  as  those  of  the  sun- 
flower, showed,  in  the  arrangement  of  their  flowers,  some  tend- 
ency towards  the  perfection  of  the  flower  cluster  as  a  unit. 


4i 6  Minnesota  Plant  Life. 

Especially  in  the  flowering  dogwoods  and  dwarf  cornels,  with 
their  conspicuous  bracts  below  the  heads  of  flowers,  did  there 
arise  an  adaptational  response  to  the  tastes  and  habits  of  insects, 
equivalent  to  that  secured  in  sunflowers  by  the  specialization  of 
the  ray  flowers.  In  the  bunching  of  the  edible  fruits  of  dog- 
woods and  in  their  high  coloration,  the  fruit-cluster,  as  such, 
became  a  definite  factor  in  the  mechanism  of  seed  distribution ; 
for  the  aggregation  of  the  fruits  made  them  more  attractive  to 
birds  and  animals,  therefore  more  likely  to  be  disseminated  than 
if  they  had  been  scattered  loosely  over  the  general  surface  of 
the  plant.  In  composites,  winged  distribution  has,  for  the  most 
part,  been  adopted,  and  in  this  family  highly  colored,  pulpy  and 
edible  fruits  do  not  exist.  The  aggregation  of  the  flowers,  how- 
ever, is  perfected  and  the  co-operation  of  the  calyx,  from  which 
the  pappus  is  formed,  makes  the  distribution  of  the  fruits  quite 
as  certain  as  among  the  dogwoods. 

A  sunflower  head  may,  upon  the  whole,  be  regarded  as  the 
most  perfect  structural  response  to  the  static  conditions  of  the 
plant  world,  just  as  the  human  head,  with  its  wonderfully  per- 
fected brain  and  sense  organs,  may  be  regarded  as  the  highest 
structural  response  to  the  dynamic  conditions  of  the  animal 
world  and  of  animal  life. 


Chapter   XL. 


Adaptations  of  Plants  to  their  Surroundings. 

if 

It  has  already  been  remarked  that  plants  which  resemble  each 
other  in  external  form  must  not  for  that  reason  alone  be  con- 
sidered as  related.  Indeed,  quite  the  opposite  is  often  true,  and 
plants  that  are  outwardly  very  dissimilar  are  found  upon  careful 
examination  to  bear  the  marks  of  kinship.  Thus,  the  locust 
tree  and  the  pea  vine  are  really  connected  with  each  other  much 
more  intimately  than  are  locusts  and  ashes,  although  the  latter 
are  similar  in  size,  in  habit  of  growth  and  even  in  the  production 
of  such  special  types  of  starch-making  organs  as  pinnately-com- 
pounded  leaves.  Plants  may,  however,  for  purposes  of  investi- 
gation be  arranged  in  groups  according  to  their  adaptations  to 
the  various  conditions  of  life  and  growth.  Such  adaptational 
groups  will  include  plants  of  widely  different  genealogy,  but 
throughout  there  will  be  discovered  certain  similarities  of  struc- 
ture and  habit.  Thus,  for  example,  among  aquatic  plants  there 
are  often  striking  likenesses  in  structure  between  comparatively 
unrelated  forms,  and  it  is  in  many  instances  a  puzzling  problem 
to  determine  just  which  structural  resemblances  are  indicative 
of  true  relationship  and  which  are  indicative  of  similar  adapta- 
tions to  similar  conditions.  The  submerged  leaves,  for  illustra- 
tion, of  the  water  crowfoot  or  water  buttercup  are  in  general 
appearance  not  particularly  different  from  the  submerged  leaves 
of  the  bur-marigold,  in  both  plants  those  leaves  produced  un- 
derneath the  surface  of  the  pond  in  which  they  live  are  dis- 
sected into  fine,  threadlike  portions.  Again,  the  quillworts, 
plants  belonging  to  the  fern  alliance,  bear  the  same  type  of 
cylindrical  hollow  leaves  that  is  distinctive  of  the  water  lobe- 
lia— a  member  of  one  of  the  highest  families  of  flowering  plants. 
Or,  passing  to  plants  of  a  different  habit  of  growth,  it  may  be 
noted  that  the  curious,  compressed  forms  of  vegetation  charac- 
teristic of  cacti  are  almost  exactly  reproduced  in  members  of 

28 


4i 8  Minnesota  Plant  Life, 

the  unrelated  spurge  family  at  the  Cape  of  Good  Hope.  The 
pitcher-plant  and  sundew  have  developed  apparatus  for  catch- 
ing small  insects  and  converting  them  into  food  for  their  own 
uses,  and  somewhat  similar  contrivances  are  met  with  in  the 
bladdcrworts  and  butterworts ;  but  the  two  groups  of  plants,  so 
far  as  true  relationship  goes,  are  very  widely  separated.  With 
such  facts  in  mind,  it  is  apparent  that,  if  genealogical  connection 
be  ignored,  plants  may  be  grouped  according  to  their  adapta- 
tions. By  this  means  certain  interesting  truths  may  be  em- 
phasized concerning  the  influence,  upon  plant  structures  and 
habits,  of  the  surroundings.  Before  entering  upon  any  discus- 
sion of  the  various  adaptational  groups  of  plants  represented  in 
Minnesota,  such  as  water  plants,  desert  plants,  carnivorous 
plants,  perching  plants,  mat  plants,  wand  plants,  shade  plants, 
sun  plants,  rock  plants,  marsh  plants  and  a  number  of  others,  it 
may  be  briefly  noted  what  are  the  principal  external  conditions 
to  which  plant  structure  and  habits  are  adapted. 

Gravity.  A  plant,  like  any  other  natural  object,  must  main- 
tain itself  under  the  constant  influence  of  the  force  of  gravity, 
and  it  is,  therefore,  necessary  that  it  should  be  architecturally 
well  constructed.  An  imperfectly  constructed  tree  trunk  could 
not  bear  the  weight  of  its  branch-system,  nor  of  its  thousands 
of  leaves  and  possibly  of  fruits,  unless — precisely  as  in  works  of 
man,  such  as  elevators,  aqueducts  or  bridges — the  laws  of  en- 
gineering had  been  obeyed.  Certain  necessary  ratios  exist, 
therefore,  between  the  thickness  of  tree  trunks,  the  tenacity  of 
the  wood,  the  height  of  the  tree,  the  number  of  branches,  and 
the  angles  at  which  they  stand  upon  the  main  axis.  For  this 
reason  a  limit  is  fixed  for  the  height  of  land  vegetation,  beyond 
which  it  is  extremely  difficult  to  pass.  If,  however,  in  the  life 
of  the  plant  some  method  is  found  by  which  support  can  be 
obtained  from  without,  much  longer  stems  can  then  be  produced 
and  they  can  remain  of  slenderer  habit.  Thus  the  climbing 
bittersweet,  the  wild  grape  vine,  the  trumpet-creeper,  the  pipe- 
vine,  or  the  bean,  are  enabled  to  produce  stems  much  longer  in 
proportion  to  their  thickness  and  strength  than  would  be  pos- 
sible if  they  did  not  utilize  neighboring  vegetation  to  help  bear 
the  weight  of  their  leaves,  twigs,  flowers  and  fruits.  The  sup- 
port that  is  obtained  by  a  plant  stem  need  not  necessarily  con- 


Minnesota  Plant  Life. 


419 


sist  of  the  vegetation  around  it,  but  the  stem  may  lie  flat  upon 
the  ground,  as  does  the  strawberry  runner.  Thus  supported,  it 
can  remain  slim  and  fragile,  but  it  could  not  do  this  if  it  main- 


FIG.  211.— Bur  oak  and  bracken  fern.     Illustrates  relation  between  strength  of  stem  and  the 
weight  to  be  borne.     After  photograph  by  Hibbard. 

tained  an  erect  habit.  Again,  water  surrounding  the  stem  and 
leaves  of  a  plant  may  furnish  the  necessary  support,  and  the 
plant  is  free  to  produce  slender  organs  which  collapse  when 


420  Minnesota  Plant  Life. 

removed  from  the  water  that  buoys  them  up.  Thus,  in  the 
pipewort,  which,  from  the  bottom  of  a  lake,  lifts  a  thread-like 
stem  ten  feet  or  more  in  length,  an  organ  is  formed  that  could 
not  be  thus  developed  under  ordinary  terrestrial  conditions. 

A  great  many  other  adaptations  besides  these  simple  ones  of 
length  and  thickness  of  shoots  might  be  discussed  at  this  point. 
For  example,  it  is  necessary  that  seeds  or  fruits,  borne  at  the 
tops  of  trees,  should  not  be  of  such  structure  that  they  would  be 
broken  and  injured  by  falling  to  the  ground.  Cocoanut  seeds, 
therefore,  which  are  heavy  and  are  produced  at  a  considerable 
height,  have  thick,  hard  shells  and  are  not  injured  by  their  fall. 
A  definite  relation  commonly  exists  between  the  stem  of  a  leaf 
and  the  blade,  or  flat  portion,  so  that  the  leaf  is  extended  in  a 
position  such  that  its  leaf-green  can  do  the  work  of  starch-mak- 
ing under  the  influence  of  sunlight.  So  the  stems  of  large 
leaves  are  generally  strong  and  often  of  a  half-cylindrical  shape, 
giving  the  strength  of  an  arch  to  the  lower  surfaces.  The  net- 
work of  the  large  leaf  is  stronger  than  that  of  the  small  leaf,  just 
as  a  large  umbrella  must  have  a  stronger  frame  than  a  child's 
parasol.  If  leaves  or  fruits  are  produced  close  to  the  ground 
they  may  become  larger,  while  remaining  more  delicate  in  struc- 
ture, than  if  they  were  produced  at  a  considerable  height.  In 
the  one  instance  the  fall  would  be  harmful,  while  in  the  other 
the  influence  of  the  wind  would  enter  as  a  factor. 

Mechanical  forces.  Besides  being  exposed  to  the  force  of 
gravity  acting  constantly  upon  its  structure,  and  consequently 
rendering  due  attention  to  strength  of  materials  a  prime  requi- 
site in  plant  architecture,  the  organism  is  subjected  to  various 
forces  which  would  tend  to  demolish  it  unless  it  met  them  with 
properly  constructed  areas.  As  examples  of  such  agencies,  there 
might  be  mentioned  currents  of  air,  which  if  violent  are  often 
known  to  damage  the  bodies  of  plants;  currents  of  water,  to 
which  plants  growing  in  rapid  streams  are  particularly  exposed ; 
the  action  of  waves,  to  which  the  various  surf  plants  must  adapt 
themselves ;  and  the  pressure  of  soil,  air  and  water,  by  which  the 
different  parts  of  plants  are  constantly  affected.  In  erect  ter- 
restrial vegetation  elasticity  is  to  a  certain  degree  a  requisite  of 
structure.  This  is  particularly  true  of  such  stems  as  are  slender, 
unsupported,  and  exposed  to  the  influence  of  wind  or  surf. 


Minnesota  Plant  Life. 


421 


Beautiful  examples  of  elastic  plant  organs  are  furnished  by  any 
field  of  grain  over  which  a  gust  of  wind  is  passing.  The  stems 
with  their  heavv  heads  of  fruit,  under  the  breeze  bend  almost  to 


FIG.  212.— Willows  and  bulrushes.     The  latter  are  typical  surf-plants.     After 
photograph  by  Williams. 

the  ground,  then  as  the  air  becomes  calmer  elastically  swing  back 
again  into  the  erect  position.     Or,  when  it  is  blowing  a  great 


422  Minnesota  Plant  Life. 

gale  along  the  lee  shore  of  some  Minnesota  lake,  one  may  see 
the  bulrush  stems  beaten  into  the  water  by  the  wind  and  surf, 
only  to  rise  again  erect  and  unharmed  when  the  waves  are 
calm.  Such  elasticity  is  procured  by  special  structural  areas 
in  the  stem,  disposed  in  highly  accurate  fashion  so  as  to  take 
up  the  lateral  strains  evenly  and  effectively.  The  cross-section 
of  a  bulrush  stem  shows  it  to  be  as  cunningly  constructed  as  the 
finest  bridge-truss,  with  girders,  flanged  in  the  regulation  style, 
made  up  of  the  so-called  "tension  pieces"  and  "compression 
pieces"  of  the  architect,  and  constituting  an  altogether  admi- 
rable piece  of  structural  engineering.  Such  contrivances  are 
not  needed  by  plants  growing  under  other  conditions  and  will 
not  be  found.  Elasticity,  for  example,  is  not  a  noteworthy  char- 
acteristic of  the  stem  of  submerged  aquatic  plants  living  in 
quiet  pools ;  but  if  the  stem  grows  in  running  water  it  is  some- 
times more  elastic.  Roots,  in  general,  being  underground  in 
their  habit,  are  not  so  much  exposed  to  occasional  displacing 
forces  as  are  stems  and,  therefore,  are  by  no  means  so  elastic. 
It  is  easy  to  compare,  in  these  regards,  a  grass  stem  and  a  grass 
root.  If  the  living  erect  stem  of  a  rye  plant  is  bent  down  it 
quickly  resumes  its  original  position ;  but  if  the  root  is  bent  to 
one  side  the  resumption  is  but  slight,  or  there  is  no  resilience. 

In  certain  parts  of  the  world,  where  heavy  falls  of  snow  occur, 
a  weight  is  in  this  way  piled  upon  the  branch  system,  and  the 
plant  perhaps  responds  to  such  a  climatic  state  by  growing  in 
the  form  of  a  flat,  prostrate  shrub,  as  many  of  the  heaths  have 
done.  Or,  if  it  be  a  tree,  it  learns  to  produce  strong  drooping 
lateral  branches  like  those  of  the  spruces.  When  grown  in  a 
lawn,  these  trees  retain  the  droop  of  their  branches  or  branch- 
lets — originally  a  structural  device  for  shedding  masses  of  snow, 
that  might  otherwise  break  the  branches  by  their  weight. 

Plants  that  produce  abundant  and  heavy  fruits  must,  if  they 
support  the  weight  of  these  fruits,  develop  strong  branch  sys- 
tems, or  otherwise  the  body  of  the  plant  will  be  broken.  Of 
this  the  apple  trees  of  orchards  furnish  good  examples.  The 
branches  of  the  apple  are  pulled  into  a  more  horizontal  posi- 
tion by  the  increasing  weight  of  the  fruit  and  many  of  them 
actually  droop.  The  main  branches  will,  however,  be  found  to 
be  strong  and  well  buttressed  against  the  trunk.  Very  often, 


Minnesota  Plant  Life. 


423 


under  a  heavy  branch  the  trunk  of  the  tree  is  especially  strength- 
ened to  bear  the  weight.  And  so,  too,  against  the  massive 
roots  of  a  tree,  the  trunk  is  often  buttressed  because  it  is  against 
these  points  that  the  pressure  is  exerted,  when  the  tree  top  is 
pushed  laterally  by  the  wind.  Plants  with  comparatively  slen- 
der branch  systems  may  mature  large  fruits  if  they  let  these 
fruits  lie  upon  the  ground.  This  is  the  device  adopted  by  the 
gourd  family,  and  the  gigantic  pumpkins  and  squashes  which 
are  so  often  exhibited  could  scarcely  be  borne,  except  under 
very  exceptional  conditions,  upon  plants  that  carried  the  whole 
weight  of  such  enormous  bodies  themselves.  Some  plants,  it 
is  true,  manage  to  suspend  extremely  heavy  fruit  areas.  Thus, 
the  banana  forms  a  bunch  of  fruits  weighing  in  the  aggregate 
some  scores  of  pounds.  But  it  is  borne  close  to  the  main  trunk 
and  is  hung  in  such  a  way  that  the  strain  is  not  unbearable. 
Cocoanuts,  which  form  heavy  fruits  at  a  considerable  height, 
have  them  placed  close  to  the  center  of  the  tree,  not  out  near 
the  tips  of  the  branches  like  those  of  the  apple. 

The  relation  between  the  sizes  of  leaves  and  their  exposure 
to  the  winds  has  already  been  mentioned.  It  is  not  possible  for 
large,  thin  and  delicate  leaves  to  maintain  themselves  under 
climatic  conditions  in  which  heavy  winds  are  prevalent.  If  large 
leaves  occur  in  windy  districts,  their  edges  are  strengthened  by 
special  adaptations  of  the  leaf  network.  Very  beautiful  ex- 
amples of  strengthening  devices  for  the  edges  of  leaves  may  be 
seen  in  milkweeds,  basswoods  or  catalpas.  In  the  latter  tree, 
especially,  the  edges  of  the  large,  heart-shaped  leaves  are  faced 
by  arch  after  arch  of  network,  making  the  margin  of  the  leaf 
very  strong  against  any  lateral  tearing  agent. 

A  consideration  of  the  points  which  have  been  thus  briefly 
presented  will  show  how  reasonable  it  is  that  the  longest 
stemmed  plants  in  the  world  should  be  oceanic,  for  such  stems 
have  water  on  every  side  to  support  them.  It  will  be  equally 
apparent  how  reasonable  it  is  that  the  most  massive  plant  struc- 
tures and  the  strongest  should  be  the  trunks  of  trees  on  land, 
for  these,  of  all  plant  organs,  have  the  greatest  need  of  strength 
if  they  are  to  perform  their  work  and  meet  the  forces  to  which 
they  are  subjected.  The  difference  of  elasticity  between  differ- 
ent plants  growing  under  different  conditions,  or  between  two 


Minnesota  Plant  Life. 

differently  conditioned  organs  of  the  same  plant,  will  appear 
altogether  comprehensible.  After  such  facts  have  become 
familiar  it  should  not  be  difficult  to  infer  something  of  the  his- 
tory of  a  plant  from  its  general  architectural  construction.  The 
droop  in  the  branches  of  a  spruce  tree  comes  to  have  its  sig- 
nificance, and  the  prostrate  bodies  of  the  cranberry  or  par- 
tridgeberry  tell  a  similar  story  of  the  flattening  effect  produced 
by  heavy  falls  of  snow. 

Heat.  Another  natural  force  to  which  plants  must  necessa- 
rily adapt  themselves  is  that  of  heat.  Therefore,  under  different 
temperatures  different  forms  and  habits  of  vegetation  may  arise. 
The  range  of  temperature  under  which  dormant  life  can  be 
maintained  is  apparently  a  pretty  wide  one — between  400  and 
500  degrees  centigrade.  The  spores  of  some  bacteria  can  en- 
dure boiling  for  an  hour  or  more  and,  for  a  short  time,  a  dry 
heat  somewhat  higher,  while  certain  seeds  have  been  exposed 
for  a  season,  without  killing  them,  to  the  low  temperature  of 
liquid  aid.  But  the  limits  of  plant  growth,  so  far  as  regards  tem- 
perature, are  considerably  narrower.  A  few  blue-green  algae 
are  able  to  maintain  themselves  in  hot  springs,  the  waters  of 
which  would  burn  the  hand,  while  the  little  red-snow  plant 
grows  upon  snowdrifts  on  mountain  tops.  Between  these  limits 
— scarcely  100  degrees  centigrade — are  the  temperatures  at 
which  active  plant,  life  and  growth  is  possible. 

The  form  of  plants  is  quite  different  under  an  average  low 
temperature  from  that  which  is  developed  in  areas  of  greater 
warmth.  So,  therefore,  a  very  characteristic  arctic  vegetation 
arises  in  contradistinction  to  that  of  the  tropics.  A  comparison 
of  polar  with  tropical  vegetation  will  serve  to  indicate  what  are 
the  influences  upon  plant  form  and  structure  of  relatively  high 
and  relatively  low  temperature.  For  the  most  part  the  vege- 
tation of  the  polar  regions  is  dwarfed,  consisting  of  low,  tufted 
plants,  little  shrubs,  stunted  herbs,  mosses  and  lichens.  In  such 
regions  the  great  luxuriant  trees  and  herbs  of  the  tropics  are 
unknown.  So,  in  the  matter  of  size,  the  poles  and  the  tropics 
favor  just  the  opposite  sorts  of  plants.  In  polar  regions  there 
is  only  a  short  growing  season  and  during  the  rest  of  the  year 
the  temperature  is  so  low,  and  the  illumination  so  poor,  that 
plants,  like  many  of  the  animals,  are  compelled  to  pass  into  a 


Minnesota  Plant  Life.  425 

dormant  condition.  Not  all  of  them  hibernate  in  the  same  way. 
A  few  polar  species  are  annuals,  shooting  up  from  the  seed  dur- 
ing the  short  polar  summer,  rapidly  maturing  their  flowers  and 
fruits,  and  passing  the  long  cold  winter  as  little  plantlets, 
wrapped  up  in  their  protective  seed  coats.  There  are,  however, 
a  greater  number  of  biennial  and  perennial  polar  plants.  Some 
of  these  are  shrubs,  like  the  poplars  and  willows,  which  grow  a 
very  little  from  year  to  year,  quickly  mature  their  flowers  and 
fruits,  and  pass  the  winter  in  a  leafless,  dormant  state.  Such  a 
rhythm  in  the  plant,  established  to  meet  the  rhythm  in  the  outer 
world,  results,  as  has  been  previously  noted,  in  that  general 
habit  of  shedding  the  leaves  which  characterizes  so  many  plants 
of  the  polar  and  temperate  regions. 

Besides  their  dwarfed  size  and  their  various  habits  of  hiberna- 
tion, plants  of  cold  regions  exhibit  numerous  protective  devices 
against  the  cold.  The  seed  coats  are  thick,  and  sometimes  the 
seeds  are  inclosed  in  warm  fruits ;  the  leaves  and  stem  are  often 
clothed  with  hairs ;  the  young  twigs  are  covered  over  with  pro- 
tective scales,  forming  the  well-known  object  that  is  called  a 
bud;  and  "warming-up  colors"  are  developed,  especially  where 
there  is  need  for  them  to  protect  the  delicate  portions  of  the 
plant.  The  ends  of  the  shoots  are  particularly  rich  in  the  warm- 
ing substances.  Peat-mosses  are  good  examples  of  this,  for  in 
a  great  many  of  them  the  ends  of  the  branches  are  violet,  red 
or  purple,  while  lower  down  they  remain  green.  Bud  scales 
are  commonly  purple,  and  alpine  and  polar  flowrers  are  more 
likely  to  be  blue  or  violet  than  yellow  or  red.  By  this  means 
the  temperature  of  a  flower  in  which  the  delicate  pollen  spores 
are  formed,  or  the  temperature  of  a  young  twig,  surrounded  by 
its  purple  bud  scales,  is  raised  somewhat,  and  the  unfavorable 
influence  of  the  cold  is,  to  some  extent,  counteracted.  The 
efficiency  of  the  "warming-up  color"  may  be  tested  experiment- 
ally by  any  one  who  cares  to  take  the  trouble.  If  two  similar 
thermometer  tubes  are  selected  and  around  the  bulb  of  one  of 
them  a  green  leaf  is  tied,  while  around  the  bulb  of  the  other  a 
purple  leaf,  such  as  that  of  the  beet  or  of  certain  begonias,  is 
wrapped,  and  the  two  thermometers  are  then  laid  in  the  sun, 
after  a  short  time  it  will  be  found  that  the  one  with  the  purple 
leaf  is  registering  from  six  to  ten  degrees  higher  than  the  other. 


426  Minnesota  Plant  Life. 

So,  too,  if  a  thermometer  bulb  is  imbedded  in  a  bunch  of  violets 
and  laid  in  the  sun,  while  another  is  imbedded  in  a  bunch  of 
primroses,  the  one  in  the  violets  will  register  a  higher  temper- 
ature after  both  have  been  lying  together  in  the  sunlight.  The 
recognition  of  the  warming-up  color  of  plants  as  a  heat-pro- 
ducing substance  gives  a  basis  for  the  explanation  of  a  great 
many  facts  that  would  otherwise  be  difficult  to  understand. 
Autumn  foliage  can  be  understood  to  be  a  definite  response  of 
the  plant  to  the  falling  average  temperature,  by  the  development 
of  a  heat-producing  area  of  its  own.  The  purple  bud  scales,  so 
common  in  trees  that  grow  outside  the  tropics,  purple  tints 
in  bark  and  in  leaves,  and  the  purplish  or  reddish  colors  of 
flowers,  are  all  recognized  as  having  the  same  general  signifi- 
cance. 

At  this  point  it  is  possible  to  understand  how,  in  a  great  many 
species,  the  color  of  flowers  may  have  originated.  As  has  already 
been  explained,  the  flower  is  essentially  the  end  of  a  branch,  and 
the  coloring  substances  which  it  contains  are  possibly  to  be 
attributed  to  protective  heat-producing  substances  present  in 
the  race-history  long  before  flowers  were  developed  as  such. 
When  flowers  came  to  be  formed  it  was  important  that  their 
pollen  should  be  protected  against  cold,  and  the  heat-producing 
colors  were  not  abandoned  but  accentuated.  In  many  blue, 
violet  and  red  flowers  it  is  possible  to  read  a  story  of  defence 
against  cold.  Hence  is  made  clear  the  reason  for  so  many 
very  early  flowers,  like  the  pasque  flower,  maple  flowers,  violets 
and  anemones,  being  purplish  in  color,  and  for  late  flowers, 
such  as  the  gentians,  having  the  same  blue  or  purple  hue.  It 
is  also  easy  to  understand  how  flowers  on  the  mountain  tops 
should  be  so  often  blue  and  that  flowers  of  the  polar  regions 
should  show  the  blue,  violet  or  reddish  tints.  With  such  facts 
in  mind  it  is  possible  to  recognize  violets  and  anemones  as,  for 
the  most  part,  northern  plants,  while  goldenrods  and  evening- 
primroses  indicate  a  southern  origin. 

Another  useful  habit  of  plants  in  polar  regions  is  their  tend- 
ency to  form  stores  of  reserved  food-material,  such  as  under- 
ground fleshy  roots,  stems  or  tubers,  or  subterranean  bulbs.  A 
great  variety  of  plants  with  such  habits  are  common  in  Minne- 
sota. On  account  of  its  provident  behaviour  the  plant  is  able 


Minnesota  Plant  Life.  427 

to  begin  the  development  of  its  flowers  and  fruits  immediately 
after  the  cold  of  winter  is  past.  When  the  growing  season  is 
short,  it  is  particularly  important  for  plants  to  ripen  their  fruits 
speedily,  or  they  will  not  be  able  to  ripen  them  at  all,  and  under 
such  stress,  in  the  plants  of  cold  countries,  very  rapidly  growing 
flowering  stems  are  produced.  Arising  from  a  fleshy  root,  a 
starch-packed  tuber  or  a  solid  bulb,  they  open  their  first  flower 
perhaps  within  a  week  after  the  snow  has  gone,  finishing  their 
fruits  before  the  end  of  spring.  Such  unnecessary  haste  in  a 
climate  like  that  of  Minnesota  indicates  an  adaptation  to  a 
colder  region ;  and  the  willows  and  poplars,  for  example,  which 
scatter  their  fruits  in  the  spring  or  early  summer,  may  be  found 
abundantly  distributed  far  to  the  northward,  even  to  the  barren 
lands  of  arctic  Canada.  More  leisurely  plants  which  do  not 
ripen  their  fruits  until  the  late  autumn,  such  as  the  grapes,  the 
gourds,  the  goldenrods  and  the  asters,  by  this  very  fact  show 
their  southern  ancestry,  and  they  will  be  found  better  developed 
in  the  south  than  in  Minnesota.  The  colors  of  flowers,  the  meth- 
ods of  hibernation  and  the  presence  or  absence  of  reserve  organs, 
such  as  bulbs,  are  all  of  much  value  in  determining  the  probable 
climatic  history  of  a  plant. 

Some  movements  in  plants  are  significant  as  indicating  an 
adaptation  against  loss  of  heat.  A  great  many  flowers  close 
at  night.  This  is  particularly  true  of  the  flowers  of  northern 
plants,  though  it  is  a  device  which  is  common  enough  in  many 
species  growing  in  regions  where  the  nights  are  cool.  By 
the  closing  of  the  flower  nocturnal  radiation  of  heat  is  dimin- 
ished and  thus  the  pollen  spores  are  protected  against  unde- 
sirable chills.  Sometimes  the  flowers  do  not  close,  but  place 
themselves  in  peculiar  sleep-positions.  Thus  a  pansy  flowrer, 
which  is  erect  in  the  daytime,  bends  over  and  faces  the  ground 
at  night.  Such  new  night  attitudes  are  not  limited  to  flow- 
ers, but  may  be  adopted  by  leaves  as  well.  At  night  the 
leaves  of  the  clovers  and  locust  trees  will  be  found  in  quite  differ- 
ent positions  from  those  which  they  maintain  during  the  day. 
The  nocturnal  position  is  probably  a  device  for  limiting  the 
radiation  from  the  plant  body.  Incidentally  it  is  useful  in  pre- 
venting the  condensation  of  dew.  Such  modified  positions  are 
sometimes  taken  suddenly,  as  by  the  leaves  of  the  sensitive 


428 


Minnesota  Plant  Life. 


plant,  an  instance  for  which  no  doubt  other  and  special  reasons 
must  be  assigned.  In  general  the  so-called  sleep  of  leaves  and 
flowers  is  an  adaptation  to  the  falling  temperature  after  the  sun 
has  set. 

When  plants  grow  in  warm  regions  they  often  manifest  a 
number  of  characters  which  are  the  reverse  of  those  to  be 
looked  for  in  plants  whose  home  is  nearer  the  poles,  or  at  a 
greater  elevation.  Thus  in  many  tropical  plants  the  produc- 
tion of  special  reserve  storage  organs  is  less  considerable  than 
among  related  species  of  colder  climes.  Buds  are  not  so  care- 
fully protected.  Furry  coats  on  the  leaves  or  twigs  are  not  so 
abundantly  formed — except,  it  should  be  said,  by  desert  plants 
in  which  furry  or  hairy  coatings  arise  as  a  protection  against 
the  too  ardent  rays  of  the  sun.  In  the  tropics,  since  hiberna- 
tion is  unnecessary,  the  various  hibernating  habits  fail  to  ap- 
pear, and  plants  do  not  so  commonly  grow  as  biennials.  The 
foliage  is  not  shed  at  the  end  of  a  definite  growing  season,  but 
normally  drops  only  when  exhausted  or  when  shaded  out  of 
existence  by  younger  foliage  between  it  and  the  sun.  The 
heat-producing  qualities,  as  manifested  by  color,  are  not  so 
marked  a  feature,  and  a  great  many  white,  yellow  and  mottled 
flowers  occur,  like  those  of  most  tree-top  orchids  in  the  equa- 
torial forests.  Evergreen  plants,  such  as  the  live-oak,  flourish 
in  the  south;  in  temperate  regions  the  oaks  are  deciduous, 
though  retaining  the  character  of  trees,  while  in  the  far  north, 
oaks,  which  would  be  trees  in  more  southern  ranges,  become 
stunted  into  little  shrubs.  It  is  possible,  in  view  of  such  facts, 
to  understand  how  dwarf  shrubs  may  occur  in  certain  genera, 
as,  for  example,  the  dwarf  cornel  among  the  dogwoods;  the 
dwarf  snowberry,  among  the  honeysuckles ;  or  the  dwarf  willow, 
among  the  willows.  It  is  possible  to  understand,  too,  how  very 
hairy  varieties  may  develop  under  climatic  conditions  different 
from  those  which  favor  the  production  of  smooth  varieties  of 
the  same  plant.  The  silky  dogwood  may  thus  be  regarded  as 
a  species  showing  in  its  foliage  a  response,  either  to  the  lower 
average  temperature,  or  to  more  direct  illumination  by  the  sun 
than  the  smooth-leafed  dogwood. 

Light.  Another  form  of  energy,  which  has  a  strong  effect 
upon  the  structure  and  habits  of  plants,  is  light.  Some  plants  are 


Minnesota  Plant  Life. 


429 


so  constructed  that  they  can  exist  with  much  less  illumination 
than  others.  This  is  particularly  the  case  if  they  are  devoid 
of  leaf-green,  and  certain  fungi  are  able  to  grow  and  mature 
their  fruit-bodies  in  absolute  darkness.  The  ordinary  green 
plant  must,  however,  be  supplied  with  illumination  sufficient 
for  the  use  of  the  starch-making  machinery, — for  leaf-green  may 
be  described  as  a  variety  of  light-engine.  Hence  there  arise, 
especially  in  the  leaf-areas  of  plants,  a  variety  of  adaptations  by 
means  of  which  the  leaves  are  spread  out  to  the  sun.  If  a  plant 


FIG.  213.— Elm  tree  growing  in  the  open.    I^ight  is  received  on  all  sides.     After 
photograph  by  Williams. 

is  growing  where  it  is  not  shaded  by  other  plants,  it  may  assume 
the  mat  or  carpet  habit  of  growth ;  but  if  it  is  shaded  by  other 
plants  it  must  become  taller  in  order  to  get  its  share  of  illumina- 
tion. The  positions  of  leaves  on  the  plant  body  are,  in  the 
economy  of  the  plant,  often  very  carefully  adjusted,  so  that  one 
leaf  fits  quite  exactly  into  the  spaces  between  other  leaves. 
Thus,  what  are  known  as  leaf-mosaics  are  formed.  The  leaves 
sometimes  make  a  rosette  at  the  base  of  the  fruiting  stem,  a 
condition  that  may  be  seen  in  a  dandelion,  in  the  evening- 


430 


Minnesota  Plant  Life. 


primrose,  or  in  the  mullein.  In  other  plants  the  shapes  of  the 
leaves  are  modified  by  their  mutual  relations  to  each  other  upon 
the  general  stem  tract.  Thus  the  one-sidedness  of  elm  or 
hackberry  leaves  will  be  found  to  be  dependent  upon  the  rela- 
tive positions  of  the  leaves  upon  the  twig.  The  side  of  the  leaf 
which  is  less  protuberant  is  the  one  that  is  shaded  by  the  leaf 
above.  The  sizes  of  leaves  vary  considerably  with  their  illumina- 
tion. Thus  the  leaves  of  plants  in  shady  places  are  generally 
larger  than  those  of  plants  growing  in  the  sun.  The  trillium 
and  jack-in-the-pulpit  leaves,  for  example,  are  considerably 


FIG.  214.— Two-leafed  wood-lilies.     These  plants  have  the  broad  leaves  of  shade  plants  and 
the  white,  conspicuous  flowers.    After  photograph  by  Hibbard. 

broader  than  the  ordinary  leaf  of  their  class.  Some  grass  leaves 
belonging  to  species  growing  in  the  deep  woods  are  decidedly 
broader  than  ordinary,  and  the  forest-dwelling  asters  and  gold- 
enrods  are  conspicuous  for  their  broad  leaves,  quite  different  in 
shape  from  the  willow-like  or  linear  leaves  of  the  sun-loving 
varieties. 

It  is  well  known  that  light  retards  that  actual  increase  in 
size  of  plant  organs  which  alone  should  be  called  growth.  It 
is  well  to  distinguish  between  growth,  meaning  by  this,  increase 


Minnesota  Plant  Life. 


43' 


in  size,  and  nutrition,  meaning  by  that,  increase  in  substance. 
Plant  stems  usually  become  more  extended  in  the  dark  than  in 
the  light.  Thus,  if  potatoes  are  allowed  to  sprout  in  the  cellar 
the  stems  produced  under  such  circumstances  are  quite  different 


FIG.  215. — Jack-in-the-pulpit.     A  shade  plant.      After  photograph  by  Hibbard. 

in  appearance  from  those  grown  in  the  ordinary  way.  Con- 
sequently, the  principal  hours  of  growth  are  those  of  the  night, 
and  corn-stalks,  if  carefully  measured,  will  be  found  to  increase 
in  length  most  rapidly  between  midnight  and  morning. 


432 


Minnesota  Plant  Life. 


While  light  has  a  retarding  influence  upon  the  growth  in 
length  of  stems,  it  has  a  strong  directive  influence  upon  organs, 
so  that  they  tend  to  place  themselves  parallel  with  the  rays,  or 
transverse  to  them,  as  their  nature  may  be.  It  is  well  known 
how  the  leaves  of  geraniums  growing  in  the  window  turn  to- 
ward the  light.  Nasturtium  vines  turn  very  quickly  and  if 
one  of  these  plants  be  put  in  the  window,  it  will  in  a  short  time 
stretch  out  its  leaves  toward  the  light  and  place  them  vertically 
to  the  rays,  thus  securing  a  maximum  illumination  for  the 
starch-making  apparatus.  Some  plants  are  not  thus  sensitive 


FIG.  216.— Reaves  of  the  sensitive  fern,  a  shade-loving  variety.     After  photograph  by  Hibbard. 

to  light.  For  example,  such  climbing  plants  as  the  ivy  or 
the  woodbine  do  not  instinctively  bend  toward  the  light,  because 
to  do  this  would  tear  them  from  their  supports ;  therefore,  they 
remain  either  insensible  to  the  directive  influence  of  light,  or 
they  actually  turn  from  it,  as  do  most  roots. 

Where  the  light  is  strong  and  abundant,  there  are  often  de- 
veloped purple  layers  on  the  under  sides  of  leaves  to  utilize  the 
surplus  light  by  converting  it  into  heat  and  employing  it  for 
the  growth-energy  of  the  plant.  This  is  true  of  such  large 


Minnesota  Plant  Life.  433 

floating  leaves  as  those  of  the  water-shield,  in  which  the  upper 
side  of  the  leaf  is  green  and  the  lower  is  purple.  The  giant  lily 
of  the  Amazon,  sometimes  cultivated  in  aquatic  gardens  of  parks 
in  Minnesota,  has  great  shield-shaped  leaves,  two  feet  or  more 
in  diameter,  and  fitted  to  float  upon  the  surface  of  the  water. 
The  edge  of  the  leaf  is  turned  up  to  prevent  ripples  from  break- 
ing over  the  surface.  While  the  upper  side  is  green  the  under 
side  is  violet  or  purplish.  The  surplus  light,  not  used  in  starch- 
making,  is,  in  such  a  leaf  converted,  by  the  purple  coloring  mat- 
ter, into  heat,  and  is  not  lost. 

When  leaves  form  rosettes  an  adaptation  for  saving  the  sur- 
plus light  is  often  noticeable.     Thus,  the  under  sides  of  dande- 


FIG.  217.— The  Virginia  creeper  on  the  walls  of  the  old  round  tower,  Fort  Snelling.  This 
plant  does  not  turn  towards  the  sun,  but  clings  to  the  shaded  wall.  After  photograph 
by  Williams. 

lion  leaves  are  commonly  purple;  and  in  a  great  many  other 
rosette-forming  plants  the  leaves  of  the  rosette  will  have  the 
color  scheme  which  has  been  described.  Hanging  or  swing- 
ing leaves  that  are  swayed  by  the  wind,  for  reasons  that 
are  sufficiently  obvious,  do  not  so  often  have  the  two  sides 
colored  in  this  manner. 

Protection  of  the  leaves  against  an  illumination  strong 
enough  to  injure  the  starch-making  machinery  within,  is  of 
various  types.  Sometimes  the  leaves  are  covered  with  scales, 
or  hairs,  thus  tempering  the  light.  Sometimes  they  are 
capable  of  changing  their  positions,  so  that  when  exposed  to 

direct  sunlight  they  shift  from  the  transverse  to  a  more  ver- 
29 


434  Minnesota  Plant  Life. 

tical  position.  This  is  true  of  leaves  in  the  compass  plant  and 
many  leaves  on  a  variety  of  herbs.  In  some  of  the  Austra- 
lian blue-gum  trees  the  leaves  stand  with  their  edges  ver- 
tical, and  similar  positions  are  very  often  maintained  by 
grasses  of  the  prairie.  When  a  plant  has  adopted  the  mat 
habit  of  growth,  indicating  the  absence  of  shade  around  it,  it 
commonly  shows  very  small  leaves,  and  no  Minnesota  mat 
plant,  lying  exposed  to  the  full  glare  of  the  sun  as  it  does,  has 
large  leaves. 

Moisture.      The  adaptations  of  plants  to  moisture  are  vari- 
ous.    Some  plants  live  quite  submerged  in  water,  and  others  find 


FIG.  218. — "  Gallery  woods,"  near  Minnesota  Falls,  valley  of  the  Minnesota,  in  the  prairie 

district.     Dependence  of  trees  upon  moisture  is  illustrated  by  their  grouping 

in  declivities.     After  photograph  by  Professor  R.  D.  Irving. 

their  most  congenial  home  in  deserts,  or  on  the  surfaces  of  inhos- 
pitable rocks ;  while  between  these  two  extremes  of  station  there 
are  a  great  number  of  intermediate  conditions  worthy  of  care- 
ful and  extended  investigation.  All  plants  need  some  moisture. 
Usually  this  moisture  is  absorbed  by  a  special  area  of  the  plant 
known  as  the  root  system.  But  leaves  are,  in  some  varieties, 
able  to  absorb  moisture,  and  aquatic  plants  characteristically 
absorb  over  their  whole  surface.  There  are  sometimes  pres- 
entations of  liquid  to  the  plant  which  it  finds  undesirable.  For 
example,  foliage  guards  itself  by  a  variety  of  devices  against 
the  heavy  rains  of  the  tropics.  Many  of  the  same  contrivances 


Minnesota  Plant  Life.  435 

may  be  seen  in  plants  of  northern  regions.  If  leaves  are  ex- 
posed to  a  heavy  rainfall  the  surfaces  are  often  lacquered  or 
waxy,  and,  by  means  of  the  coating,  rain  is  diverted  and  there 
can  be  little  danger  of  the  tissues  becoming  water-logged. 
Upon  such  leaves  grooves  or  furrows  may  be  developed. 
Through  these  the  water  is  quickly  drained  and  is  not  allowed 
to  accumulate.  Slender  points  are  distinctive  of  leaves  upon 
which  too  much  moisture  accumulates  for  the  good  of  the 
plant,  and  especially  in  tropical  forests  are  these  rain-tips,  as 
they  are  called,  ordinary  characters  of  the  leaf.  It  has  even  been 
shown  that  trees  growing  in  the  spray  of  waterfalls  develop 
leaves  slightly  different  in  shape  from  the  ordinary  leaves  of 
the  species  and  marked  both  by  furrows  on  the  upper  side 
and  by  elongated  tips.  Because  of  the  danger  of  rain  or  dews 
clogging  the  air  pores  of  leaves  these  tiny  apertures  are  in  most 
instances  assembled  on  the  lower  surfaces  of  leaves,  where 
they  are  protected.  Or,  if  they  occur  on  the  upper  surfaces 
there  are  hairs,  or  pegs  of  cell  wall  substance,  or  blooms  of  wax 
or  shellac,  which  guard  them  and  make  it  difficult  for  them 
to  be  wet.  Such  protections  against  moisture  are  particularly 
common  in  flowers,  where  it  is  essential  that  the  pollen  should 
be  kept  dry.  The  shapes  of  the  petals,  the  positions  of  the 
stamens,  and  a  variety  of  other  adaptations  make  the  wetting 
of  pollen  by  rain  improbable.  Many  fruits  are  furnished  with 
blooms  of  wax  or  with  hairs  by  means  of  which  they  easily 
shed  water.  No  such  contrivances  are  to  be  looked  for  in  the 
root  system,  or  on  the  leaves  or  stems  of  submerged  plants. 
In  water-lily  leaves  and  other  floating  varieties,  where  the  air 
pores  are  all  upon  the  upper  surface  of  the  leaf,  decidedly  waxy 
coatings  are  often  developed  to  keep  the  water  from  the 
pores.  In  some  varieties,  as,  for  instance,  the  oleander,  the 
pores  open  into  special  chambers  or  depressions,  on  the  under 
sides  of  the  leaves,  and  the  mouths  of  these  are  guarded  by 
"non-wettable"  hairs,  thus  affording  absolute  protection  to  the 
air  pores.  Many  of  the  different  positions,  shapes  and  textures 
of  leaves  and  flowers  are  to  be  ascribed  to  such  adaptations 
against  unfavorable  moistening. 

The  root  tract  of  plants,  which  in  most  instances  is  the  spe- 
cial absorptive  area,  is  fitted  by  structure  and  position  for  the 
\vork  it  has  to  do.  The  young  roots  are  furnished  with  in- 


436  Minnesota  Plant  Life. 

numerable  delicate  hairs  and  these  are  thrust  between  the  crev- 
ices of  the  soil  to  collect  whatever  moisture  there  may  be 
present.  If,  however,  the  roots  are  immersed  in  the  water  and 
hang  down  like  the  little  balancing  roots  of  the  duckweeds,  root 
hairs  are  not  then  so  abundantly  produced  because  moisture  is 
plentiful  everywhere  around  the  root  and  no  special  arrange- 
ments for  its  collection  are  necessary.  Moisture,  after  having 
been  collected  by  the  plant  through  the  activities  of  the  absorb- 
ing surfaces,  is  evaporated,  and  the  residue  is  left  in  the  plant, 
either  to  be  combined  with  other  substances  in  the  plant  chem- 
istry or  to  remain  as  a  useless  by-product.  Evaporation  and 
transpiration  of  water  vapor  are  the  ordinary  methods  by  which 
plants  rid  themselves  of  the  superfluous  water  they  have  ab- 
sorbed ;  but  some  varieties  exude  it  in  drops  from  special  water- 
excreting  glands.  Thus,  fuchsia  leaves,  if  well  supplied  with 
water  at  the  root,  will  excrete  it  in  little  drops  from  each  tooth 
of  the  leaf  margin. 

There  are  at  least  three  conditions  under  which  plants 
find  it  undesirable  to  excrete  or  transpire  water  rapidly.  One 
condition  is  that  of  the  desert,  where  there  is  very  little 
water  to  be  obtained,  and  its  rapid  transpiration  by  large 
evaporative  surfaces  would  result  in  the  wilting  of  the  whole 
plant.  Another  condition  under  which  rapid  evaporation  is 
undesirable  is  that  of  bogs  and  marshes,  and  the  reason  is  just 
the  opposite.  Here  there  is  such  an  abundance  of  moisture 
that  the  rapid  evaporation  of  it  might  maintain  an  unneces- 
sarily strong  stream  through  the  plant  tissues.  A  third  con- 
dition is  where  the  soil-water  is  impregnated  with  salts,  and 
if  rapidly  evaporated  it  would  be  as  rapidly  absorbed,  and  the 
salts  would  accumulate  in  the  plant  tissues  to  such  an  extent 
that  they  might  interfere  with  vital  processes.  Consequently 
there  are  three  groups  of  plants  so  situated  that,  while  they 
permit  water  to  evaporate  from  their  leaves  and  stem,  their 
adaptations  of  structure  are  for  slow  transpiration.  The  cacti, 
with  their  solid  stems  and  reduced  leaf  surfaces,  are  examples 
of  one  class.  The  tamaracks  and  spruces,  with  their  small 
needle-shaped  leaves,  are  examples  of  another,  and  the  sea- 
blites  and  glassworts  of  the  salt  marshes  furnish  examples  of 
the  third. 


Minnesota  Plant  Life.  437 

A  variety  of  contrivances  have  been  devised  by  plants  to 
retrench  their  evaporation.  A  simple  one  is  the  reduction  of 
the  evaporating  surface.  Thus,  leaves  become  small  or  are 
altogether  abandoned,  as  in  the  cacti  and  glassworts,  or  the 
leaves  may  become  thick  and  succulent,  as  in  the  purslanes  and 
claytonias.  Sometimes  the  skins  of  the  leaves  are  greatly  thick- 
ened and  the  air  pores  are  reduced  in  number,  as  in  the  leather- 
leafed  wintergreens  and  heaths.  Often  the  margins  of  the 
leaves  are  rolled  in  so  as  to  cover  the  air  pores  and  protect  them 
from  the  rays  of  the  sun,  as  in  many  prairie  grasses,  or  in  the 
crowberries.  Sometimes  the  leaves  are  covered  with  scales  or 
scurf,  as  in  the  buffalo-berries.  Sometimes  strong  ethereal  oils 
are  produced.  These  form  a  "scent-vapor-sheath"  around  the 
plant,  and  thus  temper  the  rays  of  the  sun.  For  such  a  reason 
many  desert  plants  are  strongly  perfumed,  as  are  wormwoods 
or  sage-brushes.  The  positions  of  the  leaves  upon  the  stem, 
and  their  shapes,  are  often  automatic,  regulative  devices,  con- 
nected with  the  evaporation  of  moisture.  Good  examples  of 
leaf-position  unfavorable  to  rapid  evaporation  are  furnished  by 
the  cat-tails,  flags  and  sweet-flags  of  marshy  places.  In  these 
the  ribbon-shaped  leaves  stand  erect  and  their  surfaces  are  not 
exposed  to  the  strong  illumination  of  the  sun.  Hence  the 
evaporation  is  slight. 

Electricity  and  magnetism.  The  adaptations  of  plants  to 
the  forces  of  electricity  and  magnetism  are  not  well  understood, 
nor  have  they  yet  been  fully  studied.  It  has  been  suggested 
however,  that  points  on  leaves,  and  spines  or  thorns,  may  in  some 
instances  be  devices  for  the  collection  of  atmospheric  electricity. 

The  soil  or  substratum.  The  relations  of  plants  to  the  soil 
are  somewhat  various.  The  texture  of  the  soil  may  be  either 
loose  or  firm.  Good  examples  of  loose  soil  are  furnished  by 
sand  dunes,  and  there  are  a  variety  of  special  sand  dune  plants, 
the  underground  parts  of  which,  meeting  with  little  resistance, 
branch  copiously  in  every  direction.  The  low  fertility  of  drift- 
ing sand  makes  such  a  broad  expansion  of  the  root  area  essen- 
tial, and  as  a  consequence  the  plants  that  are  able  to  grow 
on  sand  dunes  commonly  bind  the  sand  by  their  extensive  root 
systems,  and  may  even,  if  they  have  become  sufficiently  estab- 
lished, stop  its  drifting.  In  very  resistant  soils,  such  as  hard 


438  Minnesota  Plant  Life. 

clays,  less  copiously  branched  root  systems  are  produced.  The 
temperature  of  the  soil,  as  well  as  its  texture,  has  a  variety  of 
well-marked  effects  upon  root  areas,  as  has  also  the  consist- 
ency, the  chemical  constitution  and  the  aeration.  Soils  which 
are  very  poorly  aerated,  such  as  those  disposed  underneath 
sheets  of  water,  often  make  it  necessary  for  roots  developed  in 
them  to  send  up  aerating  tubes  or  organs.  The  well  known 
"knees"  of  the  swamp  cypresses  of  the  Atlantic  region  are  ex- 
amples of  such  organs.  A  greater  or  less  percentage  of  nitrog- 
enous substance,  lime,  magnesium,  iron  or  silica,  in  the  soil 
has  a  distinct  determining  effect  upon  the  forms  of  plants. 

Especially  interesting  is  the  soil  known  as  humus,  a  type 
which  contains  a  large  percentage  of  decaying  organic  material. 
In  such  a  soil  many  plants  without  leaf-green  are  enabled  to 
grow,  and  upon  the  humus  of  the  forest  floor  a  wealth  of  mush- 
rooms, club-fungi,  cup-fungi,  slime-moulds  and  various  related 
forms  are  displayed.  Some  seed-producing  plants,  such  as  the 
pine-drops,  the  Indian-pipe,  and  the  pine-sap,  together  with  the 
coralroots  and  others,  have  learned  to  abandon  their  leaf-green 
and  have  adopted  the  habits  of  life  similar  to  those  of  the  fungi. 

Other  living  things.  The  proximity  of  other  living  things 
is  a  condition  of  the  surroundings  that  cannot  be  disregarded  in 
the  discussion  of  plant  adaptations.  These  neighboring  crea- 
tures may  be  either  plants  or  animals.  In  response  to  their 
presence  a  large  variety  of  curious  structures  and  habits  have 
come  into  existence.  The  carnivorous  plants  catch  and  eat 
small  insects  with  which  they  come  in  contact.  Parasitic  fungi, 
such  as  the  caterpillar  fungus  or  the  fly-cholera  fungus,  attack 
certain  small  animals  and  use  their  bodies  for  a  soil  in  which 
to  grow  and  mature.  The  roots  of  louseworts,  toad-flaxes,  and 
cancerroots,  reach  out  and  attach  themselves  to  the  roots  of 
neighboring  plants,  in  some  instances  deriving  their  whole 
sustenance  in  this  manner.  A  great  variety  of  little  fungi 
develop  upon  the  leaves,  twigs,  flowers  or  fruits  of  other  plants, 
having  become  accustomed  to  eke  out  an  existence  in  this 
dependent  manner.  Many  plants  perch  upon  other  plants; 
thus,  the  Spanish  moss  of  the  south  hangs  in  festoons  from  the 
live-oaks,  and  the  orchids  of  South  America  sit  in  rows,  like  so 
many  partridges,  upon  the  branches  in  the  forest.  The  lichens 


Minnesota  Plant  Life. 


439 


of  more  northern  regions  similarly  perch  themselves  upon  the 
trunks,  or  branches,  of  trees ;  and  with  these,  too,  a  number 
of  mosses  and  liverworts  will  be  found.  Sometimes  the  perch- 
ing-plant  adroitly  selects  a  position  where  it  will  receive  more 
moisture  than  elsewhere.  So,  many  mosses  grow  around  the 
bases  of  tree  trunks, — for  the  tree  with  its  branches  serves  as  a 
drain,  by  which  the  water  of  rains  is  brought  to  the  position 
pre-empted  by  the  moss.  Lichens  and  mosses  alike  select  the 
degree  of  illumination  that  they  prefer,  and  in  northern  lati- 
tudes arrange  themselves  on  the  southern  sides  of  tree  trunks 
if  they  require  stronger  illumination,  but  on  the  northern  sides 
if  their  requirements  lie  in  the  other  direction.  Some  perching 
plants  acquire  the  habit  of  driving  their  roots  into  the  branch 
upon  which  they  stand.  Thus  originated  the  parasitism  of  the 
mistletoe  and  related  plants, — quite  a  different  method  of  its 
development  from  that  shown  by  the  cancerroots,  which  learned 
to  clutch  the  roots  of  neighboring  plants  and  drive  little  suck- 
ing organs  into  their  soft  and  nutritious  tissues. 

Another  result  of  the  mutual  proximity  of  plants  is  the 
development  of  climbing  or  twining  species.  Some  climb  by 
means  of  prickles,  thorns  or  hooks,  and  thus  the  brambles  or 
tear-thumbs  lift  themselves  upon  surrounding  vegetation. 
Others,  like  the  scouring-rushes,  brace  themselves  by  means 
of  lateral  branches  and  lift  their  slender  stems  farther  into  the 
air  than  they  could  without  assistance.  The  clematis  vines 
twist  their  leaf  stems  around  twigs  that  chance  in  their  way  and 
thus  show  a  tendency  toward  tendril  production.  Other  vines, 
like  the  smilaxes,  the  grapes,  or  the  wild  cucumbers,  develop  per- 
fected tendrils,  and  by  aid  of  these  lift  themselves  high  up  on  the 
stems  or  branches  of  neighboring  trees.  The  bittersweets, 
morning-glories  and  hops  learn  to  roll  spirally  their  slender 
stems  around  the  shrubs  that  stand  near  them,  thus  twining 
to  a  considerable  height. 

All  such  habits  must  have  arisen  by  degrees,  and  each  of 
them,  when  accentuated,  might  encourage  dependent  habits 
of  nutrition,  finally  resulting  in  parasitism.  Thus,  the  twining 
habit  of  some  morning-glory  vine  may  have  given,  in  some 
earlier  epoch,  opportunity  for  the  production  of  the  parasitic 
dodders. 


440 


Minnesota  Plant  Life. 


Intra-specific  adaptations.  A  last  group  of  adaptations 
that  may  be  considered  here  are  those  connected  with  spore 
distribution  and  seed  distribution.  It  is  necessary  for  the  well 
being  of  the  species  that  new  individuals  should  be  given  an 
opportunity  to  develop.  Thus  arose  such  simple  primitive 
adaptations  as  the  elongation  of  the  spore-bearing  plant  in 
mosses  and  liverworts,  so  that  the  spores  could  be  distributed 
over  a  wider  area.  More  perfected  apparatus  enabled  the 
spores  to  be  distributed  under  conditions  of  moisture  such  that 
they  would  most  certainly  germinate.  As  spores  assumed  a 
division  of  labor,  devices  were  adopted  by  which  the  two  sexual 
plants  might  be  produced  close  together,  thus  insuring  fecun- 
dation of  the  eggs.  The  ancestors  of  the  seed-bearing  plants 
originated  methods  of  keeping  the  young  embryo  close  to  the 
vegetative  areas  of  the  preceding  individuals  in  the  species  line. 
In  this  manner  there  arose  in  the  plant  kingdom  such  complex 
structures  as  flowers  and  seeds.  With  the  added  complexity 
of  structure  it  became  possible  for  a  great  number  of  slight 
differences  in  detail  to  exist  and  thus  the  highest  division  of 
the  plant  world,  that  of  the  seed-bearing  plants,  is  also  the  one 
in  which  the  greatest  number  of  different  species  are  described. 
A  vast  number  of  intricate  adaptations  for  pollination,  embryo- 
nursing,  and  seed  distribution  came  into  existence.  In  some 
families  of  plants  wind  pollination,  or  wind  distribution  of  seed, 
became  the  rule,  while  in  others  the  seeds  are  distributed  by 
animals  and  the  pollen  spores  are  planted  on  the  stigma  of  the 
flower  by  the  same  animate  agents.  All  the  manifold  variety 
of  form  in  flowers  and  fruits  may  be  regarded  as  due  to  adapta- 
tions, more  or  less  perfect,  by  which  the  two  sexes  of  plants  are 
developed  sufficiently  near  together,  by  which  the  young  plants 
may  derive  benefit  from  supplies  of  nourishment  produced  by 
maturer  individuals  of  their  species,  or  by  which  they  are  placed 
under  conditions  favorable  for  their  growth  and  for  the  best 
interests  of  the  species  as  a  whole. 


Minnesota  Plant  Life. 


441 


FIG.  219. — Dandelion  fruiting  in  shady  spot.     Shows  the  slender  stems  and  erect  root-leaves 
of  the  shady  habitat,  and  fruits  adapted  for  wind  distribution. 
After  photograph  by  Hibbard. 


Chapter  XLI. 

Hydrophytic  Plants. 


The  different  adaptational  groups  of  plants  may  be  best 
classified  under  three  main  divisions,  according  to  the  relation 
between  the  structure  of  the  plant  and  the  moisture  of  sur- 
rounding conditions.  For  one  series  of  plants  the  moisture 
of  the  surroundings  may  be  considerable,  for  another  it  is  ordi- 
narily slight,  while  for  the  third  a  middle  condition  is  main- 
tained. Thus,  there  are  three  principal  adaptational  groups, 
known  respectively  as  hydrophytes,  of  which  aquatic  species 
are  typical;  xerophytes,  of  which  desert  inhabitants  are  char- 
acteristic forms  ;  and  mesophytes,  in  which  group  may  be  classi- 
fied the  common  herbs  of  meadow  and  forest,  growing  under 
medium  conditions  of  moisture.  It  should  be  noted  in  pass- 
ing that  while  the  essential  structural  adaptation  of  desert 
plants  is  toward  the  slow  evaporation  of  moisture,  there  are 
also  other  conditions,  besides  those  of  desert  life,  that  make 
rapid  evaporation  undesirable.  Hence  plants  growing  in 
peat-bogs,  such  as  tamaracks  and  spruces,  or  plants  grow- 
ing in  saline  localities  are  said  to  have  the  xerophytic  type  of 
structure  and,  like  true  desert  plants,  are  slow  to  transpire 
moisture.  A  number  of  different  subdivisions  of  the  three 
main  classes  may  be  described,  and  one  should  regard  the  marsh 
and  swamp  varieties,  and  those  living  in  saline  soil,  as  furnishing 
the  transition  to  the  true  middle  group,  that  of  the  mesophytes, 
which  will  here  be  discussed  after  a  brief  account  of  the  other 
two. 

Out  of  fourteen  classes  of  hydrophytic  plants  described  by 
Eugene  Warming,  in  his  classic  work  upon  adaptational  groups 
of  plants,  eight  are  represented  in  Minnesota.  Those  unrep- 
resented are  either  arctic  or  alpine,  such  as  the  snow  plants, 
or  marine,  such  as  the  seaweeds,  and  the  mangrove  swamps 
of  oceanic  coast  lines. 


Minnesota  Plant  Life. 


443 


Plankton.  The  first  class  of  hydrophytic  vegetation  is  that 
known  under  the  technical  term  of  plankton  vegetation.  By 
this  is  meant  the  passive,  free-floating  vegetation,  not  rooted 
or  attached  to  the  soil  in  any  way.  To  this  type,  no  doubt, 
belong  the  earliest  forms  of  life  that  appeared  upon  the  crust 
of  the  earth.  Here  are  to  be  classified  many  algae — such  as 
the  familiar  water-flower  of  Minnesota  lakes,  which,  as  will  be 
remembered,  is  a  type  of  blue-green  algae.  A  number  of  Min- 
nesota varieties  belong  to  the  algal  plankton,  for  here  are  in- 
cluded not  only  the  water-flower,  but  such  forms  as  the  sphere- 
alga,  the  pond-scum,  the  desmids  and  diatoms,  the  rolling  alga 
and  a  number  of  others.  Some  of  these  plants  are  characterized 
by  the  production,  between  their  filaments,  of  interlocked  gas 
bubbles,  by  which  they  are  enabled  to  float  at  or  near  the  sur- 
face of  the  water,  and  thus  to  receive  the  sunlight.  In  many 
of  them  there  are  formed  reproductive  bodies  provided  with 
swimming  lashes,  and  by  the  aid  of  such  little  motile  cells  the 
plant  may  be  distributed  throughout  the  water  of  a  lake  or  pond. 

Another  group  of  plankton  vegetation  is  constituted  by  the 
bacteria  that  live  in  water.  A  great  many  different  sorts  are 
known ;  not  only  from  fresh  water,  but  from  the  sea.  Any  drop 
from  a  Minnesota  lake  or  river,  if  carefully  examined  by  the 
proper  methods,  would  be  found  to  contain  great  quantities  of 
the  bacterial  organisms. 

Still  another  group  of  plankton  vegetation  is  what  may  be 
called  derived,  or  secondary  plankton.  This  group  is  composed 
of  passive,  free-floating  plants  which  are,  from  their  structure, 
evidently  derived  from  ancestors  that  were  rooted.  To  this  divi- 
sion belong  the  little  water  fern  Azolla,  the  duckweeds,  form- 
ing such  abundant  scums  on  stagnant  pools,  and  the  bladder- 
worts,  together  with  some  varieties  of  liverworts,  such  as  the 
swimming  Riccia  and  the  floating  Riccia.  A  number  of  pecul- 
iar adaptations  exist  in  plants  of  the  derived  plankton.  Often 
in  their  bodies  there  are  air  chambers  by  means  of  which  they 
float.  These  may  be  seen  in  cross  sections  of  duckweed  plants 
or  Riccias.  Sometimes  the  air  chambers  are  developed  as  spe- 
cial pouches  or  bladders,  as  in  bladderworts,  where  they  also 
fulfill  another  function — that  of  capturing  small  animals  for 
food.  If  the  plant  floats  on  the  surface  of  the  water,  with  its 


444  Minnesota  Plant  Life. 

upper  side  exposed  to  the  air,  as  do  the  duckweeds,  certain 
special  structures  are  necessary.  First  of  all,  proper  counter- 
poises must  be  carried  to  prevent  the  plant  from  being  turned 
upside  down  by  the  ripples.  In  the  duckweeds  these  counter- 
poise areas  are  readily  seen  to  be  roots,  or  groups  of  roots,  but 
in  the  smallest  of  the  duckweeds  no  counterpoise  exists  as  a 
special  organ,  since  from  the  very  small  size  of  the  plants  they 
are  able  to  ride  the  waves  without  their  upper  surfaces  being  wet. 
In  one  of  the  water  ferns — the  little  Salvinia  plant,  common  in 
greenhouses,  where  it  grows  in  tanks — twro  rows  of  leaves  on 
the  floating  stem  are  thrust  down  into  the  water  and  act  as 
counterpoises;  but  in  the  wild  water  fern— the  tiny  Azolla— 
just  as  in  the  duckweeds  it  is  the  slender  roots  that  perform 
this  function.  Sometimes  skillful  combinations  of  counter- 
poises and  floating  apparatus  are  effected,  as  in  the  handsome 
water-hyacinth  of  conservatories — a  species  which  has  become 
a  great  pest  in  the  rivers  of  Florida.  In  these  plants  the  bases 
of  the  leaves,  which  arise  in  rosettes,  are  swollen  into  spongy, 
spherical  floats,  an  inch  or  more  in  diameter.  Below  such  a 
circle  of  floats  a  tuft  of  roots  hangs  down  into  the  water,  and  it 
is  quite  impossible  for  any  ordinary  gust  of  wind  to  turn  the 
plant  upside  down. 

A  second  group,  also,  of  adaptations  are  interestingly  de- 
veloped in  the  free-floating  higher  plants  by  means  of  which 
the  upper  surfaces  of  natant  organs  are  protected  against  wet- 
ting. Sometimes  the  surface  is  very  smooth  and  glistening 
and  the  water  rolls  from  it  in  the  spheroidal  form  just  as  it 
does  from  a  buttered  plate.  This  is  the  condition  to  be  ob- 
served in  the  larger  duckweeds.  The  upper  surface  of  the  small 
disc-like  stem  of  these  plants  is  somewhat  convex  and  very 
smooth.  If  water  is  poured  upon  a  group  of  duckweeds  as  they 
float  upon  the  surface  of  a  pool  it  will  roll  off  as  from  the  pro- 
verbial duck's  back,  and  will  leave  the  little  plants  as  dry  and 
glistening  as  before.  One  of  the  duckweeds,  the  three-cor- 
nered variety,  is  a  partially  submerged  plant  and  therefore  has 
not  this  power  of  shedding  water.  Another  arrangement  is 
seen  in  the  water  fern,  Salvinia.  The  upper  surfaces  of  the 
floating  leaves  are  provided  with  curious  tufted  hairs,  the  tips 
of  which  spread  out  in  three  or  four  branches  If  one  of  the 


Minnesota  Plant  Life.  445 

Salvinia  plants  is  taken  between  the  thumb  and  finger  and 
thrust  under  the  surface  of  the  water,  air  is  imprisoned  between 
the  tufted  hairs  and  the  whole  plant  glistens  as  it  is  submerged. 
If  it  is  released  it  rises  instantly  to  the  surface,  buoyed  up  by 
the  air  chambers  in  its  leaves  and  stem,  and  when  it  emerges 
the  upper  sides  of  the  leaves  will  be  found  perfectly  dry. 

Of  the  planktonic  flowering  plants  of  Minnesota,  some  de- 
pend upon  the  wind  for  pollination,  as  do  the  duckweeds,  while 
others,  such  as  the  bladderworts,  are  adapted  to  insect  pollina- 
tion. The  flowers,  therefore,  of  the  duckweeds  are  extremely 
inconspicuous,  while  those  of  the  bladderworts  are  pretty,  yellow, 
snapdragon-like  and  elevated  upon  steins  some  inches  in  length, 
so  that  they  become  noticeable  objects  and  are  easily  found 
by  wandering  bees  or  flies.  Some  free-floating  or  plankton 
plants  are  particularly  protected  against  the  attacks  of  small 
aquatic  grazing  insects  or  animals,  while  the  bladderwort  actually 
catches  and  eats  the  little  insects  that  gather  in  its  vicinity. 
The  Salvinia  plant  is  provided,  on  its  submerged  counterpoise 
leaves,  with  sharp-pointed  hairs,  and  these  stand  out  on  every 
side  in  bristling  defence.  The  sharp-pointed  hairs  are  par- 
ticularly useful  because  the  fruits  of  the  Salvinia  are  borne 
under  water,  on  the  submerged  leaves,  and  it  is  important  that 
they  should  be  protected.  The  under  sides  of  the  floating 
leaves  have  also  a  defence  of  sharp-pointed  hairs,  but  the  hairs 
on  the  upper  side,  since  they  have  a  different  purpose — that  of 
keeping  the  surface  dry — are  of  different  structure. 

Swimming  plants.  Closely  related  to  the  plankton,  or  free 
floating  vegetation,  are  the  animal-like  little  plants  that  swim 
about  in  the  water  seeking  decaying  organic  substances  upon 
which  to  feed.  They  are  abundant  in  stagnant  water  where 
there  is  sufficient  organic  food  material.  A  Minnesota  plant, 
known  to  botanists  by  the  name  of  Euglena,  is  an  example  of 
this  class  of  hydrophytes.  It  is  able,  by  means  of  its  green  color, 
to  assimilate  carbonic-acid  gas  in  the  presence  of  sunlight.  It 
takes  up  its  nitrogenous  food  from  the  organic  substances  dis- 
solved in  the  stagnant  water  and  is,  therefore,  in  its  method  of 
nutrition,  partially  dependent.  The  Euglena  plants  are  of 
microscopic  size  and  countless  myriads  of  them  in  stagnant 
pools  often  form  dense  green  scums  of  a  granular  appearance. 
Zoologists  consider  them  animals. 


446  Minnesota  Plant  Life. 

Rain-water  plants.  A  little  class  of  obscure  plants  are  re- 
garded as  of  hydrophytic  character,  since  they  live  on  rain- 
water. The  green  slime  that  forms  upon  mud  flats,  the 
bacterial  skins  that  arise  upon  soil  highly  charged  with  or- 
ganic substances,  the  blue-green  algae  that  thrive  between  the 
particles  of  sand  upon  a  moist  beach,  and  the  curious  algal  or 
bacterial  organisms  that  live  under  the  surface  of  damp  sand- 
stone cliffs,  looking  like  cobweb  threads  when  a  bit  of  the  cliff 
is  chipped  off,  might  be  given  as  examples  of  this  class. 

Attached  water  plants.  Another  adaptational  class  of  hydro- 
phytes is  furnished  by  those  species  which  live  attached  to 
stones,  either  at  the  bottom  of  streams  or  lakes,  or  upon  the 
surfaces  of  wet  cliffs,  or  those  of  bowlders  exposed  to  spray. 
Several  algae  are  found  in  such  localities.  On  \vet  cliffs  a  variety 
of  green  algae  are  to  be  looked  for,  and  here,  too,  especially 
near  waterfalls,  will  be  found  the  very  few  kinds  of  red  algae 
which  occur  in  Minnesota.  Sometimes  a  dark  brownish-purple 
skin  of  slimy  algae  may  be  seen  on  cliffs  wet  by  the  spray  of 
waterfalls,  and  this  may  be  a  growth  of  red  algae.  In  similar 
localities,  and  on  stones  in  rapidly  running  streams,  the  wire 
like,  reddish-brown  algae  of  the  Minnesota  flora  are  to  be 
sought. 

Some  higher  plants  select  similar  localities — for  example,  the 
river  moss  so  common  in  swift,  rock-bottomed  streams,  where 
it  grows  attached  to  stones  and  lies  in  tufts  with  the  cur- 
rent. The  very  curious  riverweed,  of  which  one  variety  exists 
in  Minnesota,  affixes  itself  to  stones  in  waterfalls,  and  closely  re- 
sembles an  alga.  It  is  remarkable  because  it  is  the  only  kind 
of  Minnesota  flowering  plant  that  opens  and  pollinates  its 
flowers  entirely  below  the  surface  of  the  water.  A  character- 
istic structure  of  attached  rock  plants  in  rapid  water  is  the 
holdfast,  an  organ  which  has  more  the  office  of  an  anchor  than 
of  an  ordinary  root.  In  the  river  moss  the  ordinary  slender 
root  hairs  characteristic  of  mosses  are  gathered  together  in 
strands,  thus  giving  additional  strength,  and  by  means  of  these 
little  cables  entwined  around  the  rough  corners  of  the  stones 
the  plant  holds  itself  in  place.  Plants  of  this  sort  with  hold- 
fasts and  with  submerged  vegetative  tracts  naturally  do  not 
have  abundant  air  chambers  as  in  the  floating1  varieties.  On 


Minnesota  Plant  Life. 


447 


the  contrary,  air  chambers  are  often  entirely  absent.  Where, 
too,  the  plant  is  anchored  and  free  to  undulate  its  branches 
with  every  ripple  of  the  water  there  is  little  occasion  for  strong 
mechanical  tissues,  and  no  need  for  air  pores  or  any  of  the 
devices  for  protecting-  them.  Elastic  tissue  is,  however,  some- 
what useful,  and  in  many  plants  of  this  class  it  is  formed.  A 
great  number  of  the  submerged  plants  are  slimy  to  the  touch, 
especially  in  the  ocean.  This  is  well  known  to  be  true  of  sea- 
weeds and  it  is  also  the  case  with  river  moss  and  riverweeds. 
Such  slime-coverings  may  be  useful  as  protections  during 
periods  of  low  water,  or  they  may  reduce  the  friction,  upon  the 

tissues  of  the  plant,  of  the 
flowing  water. 

Still  another  class  of  water 
plants  are  attached  under 
water  to  loose  soils,  sand  or 
mud.  The  water  eel-grasses 
may,  perhaps,  be  taken  as 
examples  of  this  group. 
Holdfasts  are  not  here  de- 
veloped simply  as  anchors, 
but  there  may  also  be 
branching  root  systems 
upon  which,  however,  root 
hairs  are  often  wanting. 

Shore  and  bar  plants. 
The  most  important  class  of 
water  plants  that  are  of 
genuine  aquatic  habit,  so 
far  as  developed  in  Minne- 
sota, are  those  which  may 
be  known  as  the  shore 
plants  and  bar  plants.  These  are  attached  or  submerged  vari- 
eties, growing  upon  loose  soil,  generally  in  communities,  with 
the  plant  body  either  entirely  submerged  or  with  the  leaves 
floating.  The  flowers  are  entirely  aerial  and  pollination  cannot 
go  on  under  the  water.  It  is  difficult  to  distinguish  this  class  of 
aquatic  plants  from  the  related  swamp  plants  that  grow  close 
down  to  the  water's  edge;  and  in  fact,  sometimes  the  same 


FIG.  220. — Vegetation  of  ravine.  The  home  of 
mosses  and  liverworts.  The  plants  in 
front  are  touch-me-nots.  After  photograph 
by  Williams. 


448  Minnesota  Plant  Life. 

kind  of  plant  appears  both  as  a  lake-border  and  as  a  marsh 
plant,  as,  for  example,  the  common  yellow  pond-lily,  which 
may  grow  upon  mud  flats,  or  more  ordinarily  out  a  little  dis- 
tance in  the  pond.  Of  the  shore  and  the  bar  plants  a  number  of 
different  varieties  belonging  to  various  groups  occur  in  Min- 
nesota. Among  the  algae,  the  bass-weeds,  so  common  as  the 
outer  zone  of  shore  plants  in  almost  every  Minnesota  pond  or 
lake,  are  most  prominent.  In  some  ponds,  especially  the 
smaller  ones  of  swales,  prairies  or  meadows,  the  water  mosses 
are  abundant.  These  have  a  different  adaptation  from  the 
river  mosses.  They  do  not  have  strong  holdfasts  by  which 
to  maintain  themselves  in  rapidly  flowing  water,  but  are  spongy 
masses  of  vegetation  and  evidently  near  relatives  of  the  carpet 


FIG.  221.— Stream-side  vegetation.      Ironweeds,  thoroughwort,  mullein,  sedge,  speedwell  and 
shrubbery.     Hydrophytic  vegetation  in  water's  edge.     After  photograph  by  Williams. 

mosses  of  the  woods.  When  they  fruit,  the  spore  cases  are 
sometimes  thrust  above  the  surface  of  the  water,  but  often 
the  spores  are  shed  below  the  surface.  To  this  group  of 
plants  may  be  referred  also  the  water  lobelias,  pipeworts,  quill- 
worts,  the  four-leafed  water  fern  and  others,  including  a  variety 
of  flowering  plants,  such  as  the  eel-grass,  the  water  buttercups, 
starworts,  water-lilies,  water  smartweeds,  floating  arrowheads, 
pondweeds  and  water  milfoils. 

A  number  of  different  and  interesting  adaptational  charac- 
ters exist  among  the  shore  plants.  Commonly,  when  alto- 
gether submerged,  they  have  very  much  divided  leaves,  as  do 
the  water  milfoils  or  water  buttercups.  If  part  of  the  plant 


Minnesota  Plant  Life.  449 

is  submerged  and  part  exposed,  the  leaves  of  the  submerged 
portion  may  be  finely  dissected,  while  the  leaves  of  the  emerg- 
ent area  are  simple  and  but  slightly  notched.  Of  this  the 
water  bur-marigold  is  an  example.  Again,  the  leaves  are  all 
submerged  and  ribbon-shaped,  as  in  the  water  eel-grass,  or 
they  may  be  quill-shaped,  with  air  chambers,  as  in  the  quill- 
worts  and  water  lobelias.  When  some  of  the  leaves  are  float- 
ing and  others  are  submerged,  the  floating  leaves  are  often 
larger  and  broader  than  the  submerged.  Thus,  in  the  float- 
ing arrowhead  the  natant  leaves  are  arrowhead-shaped,  while 
the  submerged  leaves  are  grass-like;  or,  as  in  the  water-shield 
(not,  however,  the  Minnesota  variety),  the  floating  leaves  are 
shield-shaped  and  the  submerged  leaves  are  finely  dissected. 

In  other  instances, 
as  in  the  water-lilies, 
the  difference  be- 
tween the  submerged 
and  floating  leaves  is 
not  so  great,  but  a 
slight  variation  in 
texture  is  not  hard 
to  observe.  The  fine 
dissection  of  the  sub- 
merged leaves  of  so 

FIG.  222.— Birch  trees  along  a  lake  shore.      Bar  vegeta-  mailV    aOUatic     floW- 

tion  in  background.    After  photography  by  Williams. 

ering  plants  is  evi- 
dently an  adaptation,  by  which  a  considerable  absorptive  power 
is  added  to  the  ordinary  starch-making  function  of  the  leaf.  Such 
finely  dissected  leaves  are  easily  maintained  under  water,  but 
they  would  be  likely  to  shrivel  on  account  of  too  rapid  evap- 
oration if  developed  in  many  land  forms.  The  floating  leaves, 
like  those  of  the  planktonic  vegetation,  have  adaptations  against 
moistening,  so  the  upper  side  of  the  shield-shaped  leaf  of  the 
Minnesota  water-shield  will  be  found  to  be  waxy  and  difficult 
to  wet.  The  generally  oval  or  circular  shape  of  floating  leaves, 
or  floating  stems  like  those  of  the  duckweeds  and  swimming 
Riccias,  may  be  regarded  as  a  response  to  the  equal  lapping  of 
the  waves  against  the  edges  of  the  leaf  from  all  directions. 
These  floating  leaves,  or  stems,  are  very  often  purple  on  the 
under  side,  so  that  the  surplus  light  is  converted  into  heat. 
30 


450  Minnesota  Plant  Life. 

Ribbon-shaped  leaves  are  not  so  common,  but  are  found  as 
the  submerged  variety  in  those  arrowheads  which  have  two 
sorts  of  leaves,  and  in  some  of  the  pondweeds,  as  well  as  in 
the  ordinary  eel-grass.  More  frequent  are  small,  numerous, 
narrow  leaves,  or  leaves  cut  up  into  small  and  narrow  divisions. 
A  number  of  the  pondweeds  have  such  submerged  leaves,  as 
also  the  water  milfoils,  the  waterweed,  the  mare's-tail  and  the 
water  starworts.  Least  usual  is  the  quill-shaped  leaf,  found 
however,  among  Minnesota  species  in  the  quillworts  and  in  the 
water  lobelias.  Some  of  the  pondweeds  have  broad,  thin, 
papery  leaves,  crisp  like  lettuce,  in  some  varieties,  but  of  a 
texture  different  from  that  of  land  forms.  In  general,  sub- 
merged leaves  have  no  air  pores,  or  these  are  very  sparingly 
produced.  The  epidermis  or  skin  of  the  leaf  is  not  as  strongly 
developed  as  it  is  in  the  case  of  terrestrial  leaves  that  are 
fitted  for  evaporation.  Such  leaves  are  decidedly  more  absorp- 
tive  than  are  those  of  land  plants,  this  function  being  favored 
by  the  thin  walls  of  the  skin  cells.  In  originating  the  forms 
of  aquatic  leaves  the  illumination  had  probably  something  to 
do,  and  the  elongated,  ribbon-like  leaves  on  submerged  por- 
tions of  arrowhead  plants  may  be  considered,  perhaps,  to  be 
extended  on  account  of  the  semi-darkness  caused  by  the  water. 

The  stems  of  these  water  plants  are  as  various  in  structure 
as  the  leaves.  Sometimes,  especially  where  the  soil  is  loose, 
the  stem  becomes  a  creeping,  branched  rootstock.  This  may 
be  embedded  in  the  soil  at  the  bottom,  as  in  pondweeds  and 
water-lilies,  or  it  may  creep  along  the  bottom,  as  in  water  but- 
tercups and  water  milfoils.  Sometimes  the  stem  is  short  with 
the  leaves  arranged  in  rosette  fashion — for  example,  the  water 
eel-grass  and  the  quillwort.  In  all  of  these  plants  the  stem  is 
perennial.  A  few  annual  water  plants,  however,  exist,  such  as 
the  naiads.  In  such,  the  stems  die  when  the  water  freezes  and 
the  plant  comes  up  from  the  seed  the  following  spring*.  By 
far  the  great  majority  of  water  plants  are  perennial.  The  mass- 
ive storage  organs  of  bulbous  land  plants  such  as  the  jack-in- 
the-pulpit,  or  the  onion,  are  not  typical  of  aquatic  vege- 
tation. In  general  their  stems  are  characterized  by  a  consid- 
erable development  of  the  cortical  region,  together  with  a  poor 
development  of  the  vascular  region.  Mechanical  tissue  is  not 


Minnesota  Plant  Life.  451 

at  all  abundant  in  the  greater  number  and  most  of  the  stems 
and  leaves  are  limp  when  taken  from  the  water.  In  the  cortex 
of  the  stems  and  leaf-stocks  air  chambers  are  common. 

A  variety  of  propagative  processes  are  characteristic  of  water 
plants.  Sometimes  they  pass  the  winter  in  an  evergreen  state 
at  the  bottom  of  ponds  under  the  ice.  The  eel-grasses  and 
water  starworts  do  this.  Sometimes  their  leaves  are  destroyed 
by  the  winter's  cold  and  new  ones  are  produced  from  storage 
areas  of  the  rootstock,  from  buds,  or  from  special  propagative 
bodies.  The  special  propagative  bodies  of  water  plants  are 
very  interesting.  The  pondweeds  sometimes  form  little  buds, 
that  are  separated  from  the  plant  body  and  become  distributed 
to  a  distance.  The  bladderworts  are  remarkable  for  their  pro- 
duction of  green  winter  buds,  known  as  hibernacida,  which,  in 
the  autumn  of  the  year,  or  in  the  spring,  may  be  seen  at  the 
end  of  bladderwort  stems.  In  such  buds  the  leaves  are  very 
densely  crowded  together  into  a  diminutive  green  cone  and 
the  sections  of  the  stem  with  crowded  leaves  may  be  sepa- 
rated from  the  general  plant  body  and  serve  to  propagate  the 
species.  The  calla, — rather  a  marsh  than  a  water  plant,  but 
often  living  in  the  water, — has  a  similar  habit  of  separating  win- 
ter buds  as  propagative  organs. 

The  distribution  of  different  kinds  of  shore  and  bar  plants 
depends  upon  a  variety  of  conditions, — the  character  of  the  soil, 
the  depth  of  the  water,  its  quiet  or  agitation,  and  its  tempera- 
ture. The  bass-\veeds  form  the  deep  water  zone.  Warming 
states  that  they  may  grow  in  75  feet  of  water,  but  usually 
they  do  not  grow  nearly  as  deep  as  this.  The  waterweeds  pre- 
fer shallower  water,  the  pondweeds  still  shallower,  while  the 
water-lilies  grow  close  to  the  reed-grasses  and  bulrushes.  The 
latter  are  accounted  also  as  marsh  vegetation,  because  so  much 
of  their  starch-making  surface  is  lifted  above  the  water. 

The  reproductive  processes  of  water  plants  of  this  group 
retain  the  characters  of  the  original  land  habitat,  so  far  at  least 
as  the  flowering  plants  are  concerned.  Thus,  the  flower  clus- 
ters are  always  produced  above  the  surface  of  the  water,  and 
pollination  is  effected  either  by  the  wind,  by  currents  of  water, 
by  wind  and  water  combined,  or  by  insects.  Where  the  flowers 
are  conspicuous,  as  is  true  of  water-lilies  or  pond-lilies,  insect 


452  Minnesota  Plant  Life. 

pollination  is  the  rule.  Where  they  are  inconspicuous,  as  in 
the  pondweeds  and  water  milfoils,  wind  pollination  is  the  rule. 
A  peculiar  case  is  that  of  the  eel-grass,  which  produces  its 
pollen-bearing  flowers  in  large  numbers  on  submerged  spikes. 
Each  pollen  flower  separates  from  the  spike  and  rises  to  the 
surface  of  the  water,  where  it  opens.  The  pistil-bearing  flow- 
ers are  produced  singly  on  the  ends  of  long,  thread-like  stems, 
and  open  at  the  surface  of  the  water.  The  little  pollen-pro- 
ducing flowers  are  blown  about  like  so  many  tiny  sail-boats, 
either  striking  their  stamens  against  the  stigmas  of  the  pistil- 
late flowers,  or  giving  the  wind  an  opportunity  to  carry  the 


^FiG.  223.— Trees  along  a  river  bank.     Soft  maple  and  cottonwood.      Minnesota  river. 
After  photograph  by  Williams. 

pollen  from  one  flower  to  the  other.  In  the  naiads  and  in  some 
of  the  pondweeds,  the  pollen-spores  are  carried  in  the  water, 
by  ripples  on  its  surface,  from  one  flower  to  the  other.  The 
majority  of  these  water  plants  retract  their  fruits  under  the 
surface  to  ripen  them.  Sometimes  the  stem  of  the  fruit-bear- 
ing flower  shortens  spirally,  coiling  down  into  the  water  as  in 
the  eel-grasses.  Sometimes  the  stem  curves  and  thrusts  the 
young  fruit  under  the  surface.  A  few  water  plants  mature  the 
fruits  above  the  surface  of  the  water,  and  of  such  the  Indian 
lotus  is  an  example. 


Minnesota  Plant  Life.  453 

The  depth  at  which  quondam  land  plants  are  able  to  grow  is 
in  some  instances  very  great.  Thus  Magnin  is  authority  for  the 
statement  that  one  variety  of  moss  was  found  at  a  depth  of 
nearly  200  feet  in  an  Alpine  lake,  showing  on  the  part  of  an 
originally  terrestrial  plant  a  very  high  degree  of  adaptation  to 
the  aquatic  life.  Nothing  of  this  sort  is  known  to  occur  in 
Minnesota,  and  beyond  25  feet  only  algae  and  bacteria  are 
likely  to  be  discovered,  while  into  such  deep  water  pondweeds 
and  waterweecls  rarely  extend. 

Abyssal  vegetation  and  modified  hydrophytes.  The  vari- 
ous classes  of  hydrophytes  which  have  been  discussed  may  be 
grouped  under  the  general  name  of  aquatic  vegetation.  Some 
forms  of  aquatic  vegetation  are  scarcely  represented  in  Minne- 
sota,— for  example,  hot  spring  vegetation,  the  various  seaweed 
classes,  and  snow7  vegetation.  Those  which  have  been  discussed 
comprise  the  bulk  of  Minnesota  aquatic  species.  The  class  de- 
scribed by  Warming  as  abyssal  vegetation  occurs,  however,  in 
the  deep  waters  of  Minnesota  lakes  from  50  feet  below  the 
surface  to  greater  depth.  The  darkness  is  so  great  in  such 
abysses  that  green  plants  scarcely  exist,  though  blue-green  algae 
and  diatoms  are  known  to  occur  at  depths  from  250  to  300 
feet,  being  able  to  utilize  the  extremely  small  amount  of  light 
which  penetrates  to  them.  Most  abyssal  forms  are  bacteria. 
These  occur  in  the  deepest  waters,  either  suspended  or  in  films 
along  the  bottom,  forming,  in  such  depths,  a  living  slime  or  ooze, 
as  may  be  determined  by  microscopic  examination  of  deep  lake 
soundings.  The  bacterial  vegetation  occurs  also  in  moist  or- 
ganic substrata,  such  as  the  bodies  of  animals,  where  a  large 
percentage  of  the  substance  is  water.  So  the  parasitic  bacteria 
of  disease,  either  of  plants  or  of  animals,  might  possibly  be 
described  as  forms  of  hydrophytic  vegetation.  The  bacteria, 
too,  which  live  upon  decaying  organic  matter,  such  as  the  sul- 
phur bacteria  and  the  ferment-producing  bacteria,  may  be  re- 
garded as  constituting  a  sort  of  water-loving  vegetation,  and, 
therefore,  may  be  classified  here. 

Swamp  vegetation.  The  remainder  of  the  hydrophytic 
classes  may  be  included  under  the  general  term  of  swamp 
vegetation.  This  is  the  plant  group  that  shows  itself  typic- 
ally in  swamps,  in  bogs,  in  marshes,  moors  and  tundras. 


454 


Minnesota  Plant  Life. 


Several  different  classes  exist,  all  of  them  characterized  by  the 
development  of  the  underground  portions  of  the  plant — that 
is,  the  roots  or  rootstock — in  moist  soil,  while  the  aerial  por- 


FIG.  224.— Marshy  place  at  the  edge  of  a  wood.     After  photograph  by  Murdock. 

tions,  especially  the  starch-making  areas,  are  exposed  to  atmos- 
pheric evaporation.  Like  the  majority  of  aquatic  plants,  most 
of  the  swamp  plants  are  perennial.  A  great  many  of  them 


Minnesota  Plant  Life. 


455 


produce  underground  or  prostrate  rootstocks.  These  organs 
are  underground  in  sedges,  scouring-rushes,  reed-grasses, 
sweet-flags,  cat-tails,  some  of  the  cranberries,  brambles  and 
primroses.  They  are  above  ground  and  prostrate  in  many  of 
the  heaths  and  club-mosses.  The  tissues  of  swamp  plants  are, 
as  those  of  water  plants,  likely,  in  a  variety  of  species,  to  be 
spongy.  Thus,  the  rootstocks  of  the  cat-tail,  the  rootstocks 
and  stems  of  the  scouring-rush.  the  leaves  of  many  sedges  and 
the  leafless  erect  stems  of  bulrushes  contain  a  great  number 
of  air  chambers,  giving  them  a  spongy  consistency.  Some 


FIG.  ±25.     Ferns  in  tamarack  swamp.  Iyake  Calhoim.     After  photograph  by  Hihbard. 

swamp  plants  have  special  aerating  organs,  of  which  cypress 
"knees"  are  examples.  But  these  structures  do  not  occur,  so 
far  as  I  know,  on  any  Minnesota  species. 

Most  swamp  plants  have  adaptations  for  limiting  the  tran- 
spiration of  water  from  their  shoots  and  leaves ;  that  is  to  say, 
they  are  in  this  character  like  the  xerophytes  of  desert  regions. 
Among  the  various  devices  for  reducing  transpiration  may  be 
mentioned  the  hairiness  of  many  swamp  plants,  such  as  the 
swamp-saxifrage.  Sometimes  special  pegs  are  produced  around 


456 


Minnesota  Plant  Life. 


the  air  pores,  as  in  many  sedges  and  smartweeds.     Sometimes 
that  region  of  the  leaf  where  the  air  pores  are  the  most  abundant 


FIG.  226.— Swamp  saxifrages.  The  large  root-leaves  are  adapted  to  the  shade  of  the  swamp. 
The  whole  plant  is  hairy.  Tamarack  swamp,  I^ake  Harriet.  After  photograph  by  Hib- 
bard. 

is  covered  with  a  cottony  or  woolly  coating,  as  are  the  under 
sides  of  the  leaves  in  the  Labrador  tea.     Again  wax  coatings 


aJL. 


Si* 


c 


ttfi 

tn 


«   ft 

H   * 


h 

~  ^ 

s 


O     s 


456 


Plant  Life,* 


letimes 
-undant 


At  ig 


re  the  under 


Minnesota  Plant  Life. 


457 


may  be  found  on  the  leaves,  as  on  those  of  the  rosemary,  the 
cranberries,  and  the  swamp  blueberries.  Sometimes  the  epi- 
dermis of  the  leaf  or  stem  is  very  thick,  as  in  the  bulrushes 
and  sedges.  Sometimes  the  leaves  are  leathery,  as  in  partridge- 
berries,  cranberries  and  Kalmias,  and  this  is  a  common  adapta- 
tion among  heaths.  Sometimes  the  leaves  are  small,  slender, 
and  with  but  little  surface  for  evaporation,  a  character  that 
may  be  seen  in  many  heaths  and  sedges.  In  some  varieties  the 
leaves  are  greatly  reduced,  as  in  the  scouring-rushes,  the  bul- 
rushes, some  of  the  sedges  related  to  the  cotton-grasses  and 
many  of  the  true  rushes.  Or,  if  present,  the  leaves  may  be  almost 
cylindrical,  as  in  the  Scheuchzcrias.  Again,  the  leaves  may  be 
needle-shaped,  as  in  tamaracks  or  spruces.  If  the  leaves  are 
broader  they  often  stand  vertically  so  as  to  expose  only  their 
edges  to  the  direct  rays  of  the  sun.  This  is  well  illustrated  by 
the  blue  flags,  the  sweet-flags,  the  blue-eyed  grasses,  the  yellow- 
eyed  grasses  and  the  cat-tails.  Where  these  broader  leaves  do 
not  stand  vertically  they  are  sometimes  rather  few  in  number. 
This  may  be  seen  in  the  reed-grasses  and  wild  rice.  Broad 
leaves  of  swamp  plants  are  often  rolled  in  along  the  mar- 
gins— the  same  adaptation  found  among  desert  grasses.  Thus, 
crowberry  leaves  and  many  sedge  and  grass  leaves  in  the 
swamp-dwelling  species,  are  rolled.  Sometimes  the  air  pores 
are  developed  but  very  poorly  on  the  upper  surfaces  where  the 
leaves  are  spread  out  to  the  sun.  All  of  these  characters  may 
be  regarded  as  limiting  the  transpiration  of  the  shoot  and 
leaves. 

Special  reasons  may  be  given  for  the  leaflessness  of  some 
swamp  plants,  as  for  the  bulrushes  which  belong  to  the  cate- 
gory of  surf  plants.  Their  leafless,  whip-like  sterns  are  adapted 
to  withstand  the  impact  of  surf.  The  temperature,  also,  of  the 
water  has  something  to  do  with  the  appearance  of  the  xerophytic 
characters.  They  are  more  prominent  where  the  water  is  cold. 
So  especially  in  peat-bogs  and  cedar  swamps  does  one  find  a 
variety  of  sedges,  heaths,  rushes  and  cone-bearing  trees,  all 
characterized  by  slow  evaporation. 

Reed  marshes.  To  the  class  of  reed  marshes  belong  a  variety 
of  shore  formations  and  swamp  formations  common  in  Min- 
nesota. Here  should  be  classed  the  wild  rice  beds  and  the  beds 


458 


Minnesota  Plant  Life. 


of  rushes  and  reed-grasses.  Here,  too,  should  be  included  the 
beds  of  cat-tails,  of  blue  flags,  of  arrowheads,  burweeds,  callas, 
sweet-flags  and  sedges.  In  such  regions  a  variety  of  accessory 
plants  habitually  develop,  such  as  the  swamp  butterweed,  the 
buck-bean,  the  swamp-docks  and  several  members  of  the  pars- 
ley family.  These  plants  often  arrange  themselves  in  zones 
dependent  upon  the  relative  moisture  of  the  soil,  or  upon  the 
depth  of  the  water  that  covers  the  rootstocks  and  roots.  Thus, 
along  the  borders  of  Minnesota  lakes,  bulrushes  generally  grow 


FIG.  227. — A  marsh-loving  sedge,  showing  fruit  clusters.     After  photograph  by  Hibbard. 

outside  of  reed-grasses,  and  reed-grasses  outside  of  sedges, 
showing  the  exact  adaptations  of  these  kinds  of  plants  to  the 
moisture-content  of  the  soil  and  to  the  water  covering  their  un- 
derground portions.  Most  of  the  plants  in  reed  swamps  are 
provided  with  rootstocks  by  means  of  which  they  propagate. 
The  strong  rootstocks  of  bulrushes  and  cat-tails  may  serve  as 
examples.  While  pushing  a  boat  through  a  bed  of  bulrushes  a 
careful  observer  will  notice  that  the  rushes  stand  in  rows,  and 
these  rows  designate  the  position  of  the  prostrate  rootstock  in 
the  bottom.  From  such  branching  rootstocks,  common  to 


Minnesota  Plant  Life.  459 

sedges,  cat-tails,  bulrushes  and  reed-grasses,  the  aerial  or  lateral 
branches  arise.  The  rootstock  commonly  bears  scale  leaves. 
These  may  be  well  seen  if  a  cat-tail  plant  is  dug  up  and  washed. 
Among  the  perennial  rootstock-forming  herbs,  which  are  the 
characteristic  plants  of  reed  swamps,  a  few  shrubs  are  often 
found  growing,  such  as  willows  and  alders. 

Wet  meadows.  A  second  class  of  swamp  vegetation  is  known 
as  swamp-moor  or  wet  meadow.  In  such  regions  there  is  a 
high  percentage  of  ground  water,  but  under  ordinary  conditions 
the  subterranean  portions  of  the  plants  are  not  directly  covered 
by  standing  water.  Such  meadows  exhibit  in  Minnesota  a  variety 
of  plants,  for  the  most  part  sedges,  grasses  and  rushes,  but  with 
a  strong  intermixture  of  other  plants,  including  such  varieties 
as  the  shield-ferns,  marsh-marigolds,  the  Parnassias,  some  gen- 
tians, buck-beans,  orchids,  willow-herbs  and  parsleys.  Here, 
too,  swamp-saxifrages  and  pitcher-plants  are  often  to  be  found. 
Mingled  with  the  herbage  which  is  the  predominant  vegeta- 
tion of  such  wet  meado\vs  a  variety  of  shrubs  may  grow,  in- 
cluding dogwoods,  willows,  dwarf  birches,  buckthorns,  and 
spiraeas  or  meadowsweets,  and.  in  northern  parts  of  the  state, 
heaths  or  crowberries.  A  considerable  moss  vegetation  exists 
in  such  wet  meadows,  including  sometimes  peat-mosses,  but 
also  carpet  mosses,  hairy-capped  mosses  and  others.  Some- 
times moss  meadows  occur,  forming  a  transition  to  peat- 
bogs and  peat-tundras.  In  arctic  regions  such  wet  meadows 
are  inhabited  often  by  lichens  to  the  exclusion  of  other  plants. 
As  is  also  true  of  aquatic  vegetation  these  wet  meadows  are 
tenanted  for  the  most  part  by  perennial  species. 

Peat-bogs.  A  particular  type  of  swamp  vegetation  is  the 
peat-bog.  It  differs  from  the  ordinary  wet  meadows  in  the 
chemical  character  of  its  soil.  Chalk  and  potassium  are  pres- 
ent in  peat-bogs  in  smaller  quantities  than  in  wet  meadows, 
and  it  has  been  shown  that  the  nitrogenous  content  of  peat- 
bogs is  less  than  that  of  wet  meadows.  Humus,  therefore, 
forms  better  in  wet  meadows  than  in  peat-bogs.  On  account 
of  the  low  nitrogenous  content  of  the  peat-bog  there  is  a 
poorer  development  of  bacteria  and  vegetable  remains  are, 
therefore,  better  preserved  if  sunken  in  peat  than  if  embedded 
in  the  bacterial  soil  of  a  wet  meadow.  The  distinctive  plants 


460  Minnesota  Plant  Life. 

of  peat-bogs  are  the  peat-mosses,  the  most  abundant  and  in 
some  respects  the  most  remarkable  of  all  the  mosses.  A  con- 
siderable number  of  different  species  occur  in  Minnesota. 
They  are  extremely  spongy  and  contain  a  large  amount  of 
water  in  special  cells  of  their  leaves  and  stems.  Besides  the 
peat-mosses  a  number  of  other  mosses  will  be  found  in  peat- 
bogs, with  a  variety  of  liverworts.  Here,  too,  is  the  favorite 
home  of  many  sedges,  such  as  the  cotton-grasses,  of  many  grasses 
and  lilies,  of  rushes  and  of  orchids.  Heaths  are  a  marked  fea- 
ture of  peat-bogs  and  almost  all  the  Minnesota  varieties  are  to 
be  looked  for  in  such  localities,  where  one  finds  the  Labrador 
tea,  the  Kahnias,  the  rosemarys,  the  cranberries,  the  snow- 
berries,  the  leatherleafs  and  the  bilberries.  Mingled  with  them 
are  a  number  of  other  peat-bog-dwelling  plants  belonging 
to  various  families.  Here  one  will  find  the  sundews  and 
pitcher-plants,  the  dogwoods,  brambles  and  sweet-ferns,  the 
myrtle-leafed  willow,  the  tag-alder  and  the  crowberry.  Espe- 
cially distinctive  of  such  areas  are  spruces  and  tamaracks  and 
these  are  the  most  characteristic  trees  of  peat-bogs  in  the  Min- 
nesota region.  They  are  often  very  much  dwarfed  by  the 
cold  water  and  by  the  low  percentages  of  mineral  salts  which 
these  waters  contain.  Especially  when  growing  in  the  wet 
region  of  the  bog  are  the  trees  diminutive;  and  spruce  trees 
75  years  old  and  but  little  over  an  inch  and  a  half  in  diameter 
have  been  found  in  Minnesota  peat-bogs. 

It  is  probably  on  account  of  the  low  nitrogenous  content  of 
the  water  that  carnivorous  plants,  such  as  the  pitcher-plant  and 
sundews,  have  developed  particularly  in  peat-bogs.  They  are 
able  by  their  insect-catching  habits  to  supply,  from  the  bodies 
of  their  victims,  nitrogen  to  compensate  for  the  scantiness  of 
this  element  in  the  soil. 

Most  of  the  species  in  peat-bogs  are  perennial.  On  account 
of  the  open,  meadow-like  character  of  typical  peat-bogs  the 
snow  accumulates  in  heavy  sheets  and  this  will  perhaps  account 
to  some  extent  for  the  prevalence  of  prostrate  shrubs  like  the 
heaths.  No  doubt  also  the  prostrate  habit  is  resultant  from 
the  necessity  for  slow  evaporation.  Since  the  heaths  do  not 
lift  their  leaves  into  the  air  on  erect  shoots  so  abundantly  as 
do  other  kinds  of  shrubs,  they  avoid  that  agitation  by  the  wind 
which  would  promote  evaporation. 


Minnesota  Plant  Life. 


461 


Peat-tundra.  The  type  of  vegetation  known  as  peat-moss 
tundra  is  sparingly  developed  in  Minnesota.  It  may  be  de- 
scribed as  a  kind  of  dry  peat-bog.  I  have  seen  isolated  and 


FIG.  228.     A  pitcher  plant  in  flower;  tamarack  swamp.     The  leaves  are  converted  into  insect- 
traps.     After  photograph  by  Hibhard. 

limited  peat-moss  tundra  formations  at  Lake  of  the  Woods, 
where,  on  some  of  the  rocky  islands  near  the  Northwest  Angle 


462  Minnesota  Plant  Life. 

Inlet,  dry  peat-moss  turfs  form  in  the  depressions  of  the  rock. 
Mingled  with  the  peat-moss  were  the  reindeer-moss  lichens 
and  the  bluebells  and  juniper  bushes,  which  are  such  distinctive 
rock  plants  of  this  region. 

Swamp  underbrush.  Another  type  of  swamp  vegetation  de- 
veloped in  Minnesota  is  known  as  swamp  shrub  or  swamp 
underbrush.  This  consists  for  the  most  part  of  birches,  wil- 
lows, buckthorns,  black  haws,  hollies,  dogwoods,  alders  and 
poison  sumacs.  Where  a  reed  swamp  or  wet  meadow  has 
grown  up  to  underbrush  this  sort  of  formation  appears.  When 
the  swamp  underbrush  has  arisen,  sufficient  shade  is  produced 
to  permit  the  development  of  certain  accessory  herbs  that 
would  not  otherwise  be  so  abundantly  present.  In  such  re- 
gions, for  example,  violets  and  touch-me-nots,  gentians  and 
thoroughworts  are  often  abundant.  Such  swamp  underbrush 
sometimes  grows  along  the  edges  of  peat-bogs  and  lakes  and  in 
this  situation  willows  and  dogwoods  particularly  abound.  Wil- 
lows, also,  very  often  form  rings  around  the  shores  of  small,  low 
islands,  mud  flats,  or  sand  bars  in  lakes  or  streams,  while  the 
higher  land  of  the  centre  is  occupied  by  elms,  cottonwoods, 
maples  or  basswoods.  This  is  a  very  common  example  of 
zonal  distribution  in  Minnesota. 

There  have  now  been  passed  in  review  the  principal  types 
of  hydrophytic  vegetation.  Apparently  the  strong  preponder- 
ance of  water  in  the  substratum,  as  for  the  swamp  plants,  or 
surrounding  the  plant  body,  as  for  aquatic  vegetation,  has  a 
number  of  definite  influences  not  only  upon  the  structure  of 
plants,  but  upon  their  grouping.  The  depth  of  the  water,  the 
character  of  the  soil,  the  chemical  substances  held  in  solution 
in  the  water,  the  temperature,  agitation,  or  quiet,  and  other 
conditions,  all  have  their  influence  and  it  is  not  at  all  an  acci- 
dental matter  whether  a  particular  moist  region  develops  as  a 
peat-bog,  as  a  reed  swamp,  as  a  wet  meadow,  or  as  3.  swampy 
underbrush.  In  all  the  hydrophytic  vegetation  classes  peren- 
nial species  are  predominant.  A  great  many  of  them  are 
herbs,  while  some  are  shrubs,  and  a  few  are  dwarfed  or  spe- 
cialized trees. 


Chapter  XLII. 

Xerophytic  Plants* 


The  plants  classified  under  the  general  name  of  xerophytes 
are,  in  their  selection  of  habitats,  just  the  opposite  of  aquatic 
plants.  They  grow  typically  under  conditions  of  slight  mois- 
ture and  some  of  them  are  able  to  maintain  themselves  in  the 
most  arid  regions  of  the  world.  Thus,  a  distinctive  desert 
vegetation,  such  as  may  be  found  in  the  Sahara,  or  in  the  deserts 
of  Arizona,  has  come  into  existence.  A  number  of  plants, 
although  not  inhabitants  of  the  desert,  find  it  difficult  to  obtain 
sufficient  moisture  and  assume  the  xerophytic  type  of  structure. 
Good  examples  of  these  are  the  orchids  that  live  in  tree  tops 
and  dangle  their  roots  in  the  damp  air  of  tropical  forests.  Since 
this  is  a  slow  way  of  accumulating  moisture,  such  plants  are 
often  cactus-like  in  form.  Not  being  exposed  to  the  attack 
of  grazing  animals,  as  are  the  cacti,  they  do  not  become  armed 
with  thorns  and  spines,  but  they  have  often  the  same  massive 
bodies  that  are  found  in  true  desert  plants.  A  great  variety 
of  secondary  conditions  serve  to  modify  and  regulate  the  ap- 
pearance of  xerophytic  structural  characters.  Thus,  some  xero- 
phytic plants  living  in  sand  differ  decidedly  from  others  living 
upon  rocks.  Those  developed  in  soil  rich  in  nitrogen  differ 
from  those  that  have  but  a  scant  supply  of  this  element  avail- 
able for  their  roots.  The  saline  substances  present  or  absent 
in  the  soil  may  modify  the  plants  growing  upon  it.  For  this 
reason  a  difference  arises  between  the  vegetation  of  limestone 
and  granitic  regions  and  some  plants  are  known  to  be  indica- 
tive of  limestone  soils  just  as  others  are  of  the  presence  of  quartz. 

Desert  plants.  A  variety  of  devices  are  employed  by  xero- 
phytic plants  to  regulate  the  evaporation  or  transpiration  of 
moisture.  Sometimes  during  extremely  dry  seasons  desert 
plants  abandon  their  leaf  structures  entirely,  thus  responding 
to  the  arid  conditions  quite  as  plants  of  temperate  regions  re- 
spond to  the  approach  of  winter.  Trees  in  deserts  often  drop 


464  Minnesota  Plant  Life. 

their  leaves  after  the  short  rainy  season  is  over  and  pass  into 
a  winter-like  condition,  during  which  they  evaporate  much  less 
moisture  than  would  be  necessary  if  their  leaves  were  expanded 
to  the  ardent  rays  of  the  sun.  For  this  reason,  too,  a  great 
many  desert  plants  are  annual,  and  in  the  compact  form  of 
seeds  withstand  the  dry  season  of  the  year.  When  the  rain  has 
come  again  the  seeds  germinate  rapidly  and  in  a  short  time  the 
flowering  and  fruiting  processes  are  completed.  It  is  remark- 
able, in  a  desert,  when  the  rainy  days  are  at  hand,  to  observe 
the  extraordinary  rapidity  with  which  plant  organs  of  various 
sorts  appear  upon  what  was  before  an  arid  waste. 

Many  desert  plants  develop  underground  bulbs  and  root- 
stocks  which  persist  without  sign  of  life  during  the  dry  time 
of  the  year  and,  when  there  has  been  a  short  season  of  rain, 
suddenly  put  forth  flowering  stems  and  foliage.  Another  way 
of  meeting  the  aridity  and  dryness  of  the  air  is  by  the  rolling 
up  of  the  leaves.  This  is  well  seen  in  the  buffalo-grasses,  in 
some  of  the  wormwoods  or  sage-brushes,  and  in  a  variety  of 
sedges,  grasses  and  mosses.  By  means  of  this  reduction  of 
the  evaporating  surface  at  the  critical  time,  the  desert  plants 
which  employ  these  adaptations  are  able  to  prevent  too  great 
evaporation.  Another  method  adopted  by  plants  in  arid  re- 
gions is  the  modification  of  their  leaf  positions,  and  a  number 
of  leaf-movements  are  regarded  as  protective  against  undue 
evaporation  of  moisture.  Many  plants  of  the  pea  family  in 
desert  regions  have  such  special  leaf-movements.  Still  another 
method  is  the  setting  of  the  leaves  on  edge,  as  in  compass- 
plants;  and  the  rosinweed  compass-plant  and  the  lettuce  com- 
pass-plant of  the  Minnesota  flora,  by  twisting  their  leaves  so 
that  only  their  edges  are  presented  to  the  direct  light,  illustrate 
such  adaptations.  Since  the  strongest  illumination  in  the 
northern  hemisphere  is  from  the  south,  these  compass-plants 
turn  most  of  their  leaves  so  that  the  flat  sides  face  east  or  west, 
and  thus  they  are  exposed  to  the  least  direct  sunlight  possible. 

In  the  desert  regions  of  the  world,  leaves  sometimes  hang 
from  the  stems  so  that  the  light  strikes  them  as  little  as  pos- 
sible during  the  day.  Still  another  device  for  limiting  tran- 
spiration, common  among  desert  plants,  is  the  formation  of  leaf 
structures  that  evaporate  moisture  but  slowly.  The  prismatic 


Minnesota  Plant  Life.  465 

leaves  of  pine  trees,  the  leathery  leaves  of  heaths  and  hollies, 
the  scale-covered  leaves  of  buffalo-berries  and  silverberries,  the 
slender  cylindrical  leaves  of  many  rushes,  the  ribbon-shaped 
leaves  of  many  grasses  and  sedges  are  all  examples  of  such 
protective  structures.  Some  leaves  are  fleshy  and  succulent, 
like  those  of  the  live-forever,  the  purslane,  the  spring-beauty  or 
the  portulaca.  The  leaves  of  century-plants  are  types  of  this 
kind  of  adaptation. 

Not  only  are  leaves  variously  modified,  but  stem  areas  as 
well,  in  the  above-ground  portions  of  xerophytic  plants,  re- 
spond to  the  conditions  around  them.  Thus,  some  stems  are 
leafless,  as  in  certain  of  the  cacti.  Such  leafless  stems  may  be 
somewhat  flattened  and  may  have  green  rinds  by  which  they 
carry  on  their  starch-making.  Sometimes  the  steins  are  cylin- 
drical, as  in  the  bulrush.  Sometimes,  as  in  the  asparagus,  the 
leaves  are  absent  from  the  plant  body,  or  are  reduced  to  scales 
and  their  place  is  taken  by  little  needle-shaped  branches  that 
carry  on  the  starch-making  function.  Sometimes  the  stem  is 
converted  into  a  solid  gourd-like  body,  as  in  the  melon-cacti 
and  prickly-pears.  By  such  forms  and  structures  of  leaves  and 
stems  the  transpiration  of  moisture  is  greatly  reduced. 

Another  modification  appears  in  those  plants  which  have 
coatings  of  one  sort  or  another  to  protect  the  leaves  and  stem. 
Thus,  the  bloom  on  the  leaves  of  a  century-plant,  the  hairs  and 
bristles  on  a  mullein  leaf,  the  clusters  of  dead  leaves  that  are 
retained  by  some  plants  for  a  year  or  more,  the  incrustations  of 
chalk,  wax,  slime,  shellac  or  gum,  all  have  their  value  in  re- 
ducing evaporation.  The  internal  sliminess  of  the  leaves  of  cen- 
tury-plants is  a  familiar  fact.  Well  known,  also,  is  the  resin- 
ous matter  so  commonly  seen  to  exude  from  the  leaves  of  pines 
and  their  allies.  Various  other  adaptations  exist  which  cannot 
be  discussed  at  all  fully.  The  intimate  structures  of  leaves, 
the  position  of  the  starch-making  bodies  in  the  leaves,  the 
position  and  character  of  the  air  pores,  all  have  a  significance. 

Some  plants  have  glands  the  function  of  which  is  to  secrete 
salty  deposits  on  the  leaves.  These  salty  deposits  have  a  strong 
affinity  for  moisture  and  may  serve  to  collect  it  from  the  ex- 
terior. Many  desert  plants  are  known  by  their  pungent  odor, 
very  perfect  examples  of  which  are  the  wormwoods  or  sage- 
brushes. It  has  been  shown  that  the  vapor  of  the  ethereal  oils, 
31 


466 


Minnesota  Plant  Life. 


r 


Minnesota  Plant  Life.  467 

existing  in  such  plants,  when  commingled  with  the  atmosphere 
reduces  its  permeability  to  heat,  and  thus  the  constant  exhala- 
tion of  perfume  from  the  body  of  a  wormwood  is  to  be  regarded 
as  a  device  for  tempering  the  heat  of  the  sun.  No  doubt  some 
of  these  strongly  scented  substances  are  of  value,  too,  as  dis- 
couragements to  grazing  animals.  By  all  such  adaptations  in 
the  above-ground  portions  of  a  plant  it  is  clear  that  a  reduced 
transpiration  is  effected.  The  below-ground  organs,  such  as 
the  roots  or  rootstocks  of  desert  plants,  are  often  important  as 
reservoirs  of  moisture.  Some  varieties,  like  the  wild  morning- 
glories,  produce  very  large  roots,  and  often  the  root  system 
of  a  desert  plant  is  much  greater  in  extent  than  the  above- 
ground  portion. 

A  number  of  classes  of  xerophytic  plants  exist,  many  of  them 
represented  in  Minnesota.  While  the  state  does  not  include 
any  desert  regions,  yet  there  are  numerous  tracts  upon  which 
xerophytic  plants  would  find  a  habitat — for  example,  sandy 
barrens,  dry  rocks,  sand  dunes  and  high  sand  beaches,  high 
prairies  and  meadows,  or  the  dry  branches  of  trees.  Some  of 
the  characters  of  these  different  classes  may  be  discussed  more 
in  detail. 

Rock  plants.  Rock  vegetation  is  well  defined  and  includes 
a  number  of  species  that  are  not  common  elsewhere.  A  large 
portion  of  it  is  made  up  of  mosses  and  lichens;  and  on  dry 
cliffs,  exposed  bowlders  or  crags,  as  well  as  upon  ledges  of 
rock,  a  number  of  rock  lichens  and  rock  mosses  are  prolific. 
These  plants  require  but  a  small  amount  of  water  and  are 
often  provided  with  several  of  the  special  adaptations  against 
transpiration.  The  common  little  black  tufts  of  moss  which  are 
found  upon  bowlders,  under  ordinary  conditions  look  perfectly 
dry  and  shriveled,  but  if  wet  they  quickly  revive  and  their  green 
color  becomes  more  apparent.  Many  of  the  lichens  growing 
upon  rocks  have  the  same  shriveled,  dry  appearance  betokening 
adaptations  affecting  evaporation.  In  order  to  attach  them- 
selves to  the  bare  surfaces  of  rocks,  lichens  secrete,  as  has  al- 
ready been  stated  in  the  chapter  on  lichens,  certain  acids  able 
to  corrode  limestone  or  quartz.  The  plants  cling  closely  to  the 
corroded  surface  and  they  cannot  possibly  be  detached  with- 
out destroying  them.  Some  algae  are  capable  of  living  on 


468 


Minnesota  Plant  Life. 


rocks  and  there  pass  into  a  dry,  dormant  condition,  except  when 
the  rock  is  wet  \vith  rain.  In  Minnesota  a  number  of  pinks, 
rock-roses,  purslanes  and  Canterbury-bells  make  their  home 
upon  .rocky  ledges  or  shores.  Here,  too,  there  are  to  be  met 
with  a  variety  of  ferns,  such  as  the  cliff-brakes,  the  polypody 
and  others.  With  them  may  be  found  numerous  grasses,  plan- 
tains, verbenas,  evening-primroses,  ragweeds,  capers,  and  saxi- 
frages. Upon  such  rocky  ledges  may  also  be  discovered,  espe- 
cially in  the  northern  part  of  the  state,  the  juniper  bushes  and 
the  ground-hemlock.  Rock-succulents  are  not  common  in 


FIG.  230. — Growth  of  hardwood  trees  upon  a  rocky  island.     Northwest  angle,  I,ake  of  the  Woods. 
After  photograph  by  the  author. 

Minnesota;  but  the  prickly-pear  cactus  of  Pipestone  and  the 
rock  purslane  of  the  Minnesota  valley,  are  examples.  More 
often  grasses  with  rolled  up  leaves,  junipers  with  needle-shaped 
or  scaly  leaves,  saxifrages  with  hairy  leaves  and  other  adapta- 
tional  types  will  be  present.  The  larger  rock  plants,  needing 
more  soil  for  their  root  areas,  grow  in  crevices  and  may  be 
found  abundantly  wherever  the  rocks  have  been  split  and  soil 
has  formed  in  the  clefts. 

Moss  heaths.     Another  class  of  xerophytic  vegetation  in- 
cludes the  moss  heaths.     These  are  dry,  moss-covered  stretches. 


Minnesota  Plant  Life.  469 

Mingled  with  the  mosses  there  may  sometimes  be  small  shrubs 
or  herbs.  Such  moss  heaths  are  to  be  found  upon  some  of  the 
islands  in  Lake  of  the  Woods  and  Rainy  Lake. 

Lichen  heaths.  A  related  class  may  be  described  as  lichen 
heath.  The  characteristic  plants  of  this  formation  are  the  rein- 
deer mosses ;  and  very  beautiful  examples  exist  along  the  north- 
ern limits  of  the  state.  The  dry,  rounded,  thin-soiled  islands 
in  Lake  Saganaga  give  perfect  examples  of  lichen  heaths.  A 
few  trees  and  shrubs  are  present,  but  the  characteristic  and  pre- 
dominant vegetation  is  composed  of  reindeer  mosses  with 
little  heaths,  grasses,  rushes,  verbenas,  and  vetches  mingled  with 
them. 

Shrubby  heather.  Another  class  not  so  extensively  repre- 
sented in  Minnesota  as  elsewhere  is  the  shrubby  heather,  in 
which  the  ground  is  covered  by  little  heath  bushes,  mosses, 
club-mosses  and  junipers.  Yet  such  heaths  to  a  limited  extent 
exist  in  the  northern  part  of  the  state.  Mingled  with  the  heaths 
proper  are  a  number  of  composites,  such  as  those  goldenrods. 
asters,  and  fleabanes  which  prefer  dry  open  localities. 

All  of  these  rock  and  heath  groups  of  plants  are  strongly 
xerophytic  in  their  general  features.  They  are,  in  many  in- 
stances, to  be  regarded  as  responses  to  sterility  of  soil  rather 
than  aridity  of  climate. 

Sand  plants.  Very  closely  connected  with  rock  vegetation 
is  the  sand  vegetation  of  dunes,  beaches  and  barrens.  The  sand 
is  lacking  in  moisture,  which  percolates  through  it  readily, 
lacking  also  in  nitrogenous  substances  and,  therefore,  to  some 
degree  not  unlike  a  rock  tract,  hence  naturally  presenting 
similar  types.  A  great  many  plants  which  can  grow  upon  rocks 
can  also  grow  upon  sand  dunes  and,  as  a  result,  in  the  northern 
part  of  the  state,  junipers,  for  instance,  occur  in  about  equal 
frequency  upon  bare  rock  ledges  and  upon  sand  dunes.  A 
special  type  of  sand  vegetation  is  that  of  sandy  beaches,  where 
the  proximity  of  lake  water  makes  the  soil  moister  than  it 
would  otherwise  be.  For  this  reason  the  plant  inhabitants  of 
beaches  are  often  mesophytic  rather  than  xerophytic  in  char- 
acter, while  close  to  the  water's  edge  true  hydrophytes  may 
establish  themselves.  Dunes  are  particularly  characterized  by 


470 


Minnesota  Plant  Life. 


sand-binding  plants,  such  as  the  wild  rye,  the  junipers,  some 
sedges,  rushes  and  grasses.  Mingled  with  the  herbaceous 
plants  are  a  few  shrubs  and  trees,  such  as  the  hackberries,  choke- 
berries,  poplars,  oaks  and  ashes,  with  brambles  and  roses  as 
underbrush.  Sand  barrens  in  Minnesota  fall  for  the  most  part 
into  three  classes,  jack-pine-barrens,  oak-barrens  and  sandy 
wastes.  The  distinctive  plant  of  the  pine-barren,  a  common 
formation  in  the  central  portion  of  the  state,  is  the  jack-pine. 
Along  with  trees  of  this  species,  a  number  of  underbrush  plants, 
herbs,  mosses  and  lichens  establish  themselves.  Here  blueberry 
bushes  are  abundant  and  other  heaths.  In  such  woods  the  de- 


' 


FIG.  231.— Vegetation  of  sand  dunes,  Isle  saux  Sables,  I«ake  of  the  Woods.  In  the  foreground 
is  the  sand  cherry  and  scrub  poplar,  in  the  center,  a  juniper  bush  and  in  the  background, 
plums.  After  photograph  by  the  author. 

velopment  of  wand  plants  is  common,  and  in  the  autumn  the 
forest  floor  is  resplendent  with  the  yellow  heads  of  sunflowers, 
the  purple  spikes  of  blazing-stars,  and  the  white  or  blue  inflo- 
rescences of  asters.  Sandy  wastes  are  characterized  by  the  de- 
velopment of  mat  plants,  such  as  carpetweeds  and  spurges. 
Mingled  with  these  are  to  be  sought  many  rosette  plants  like 
the  evening-primrose  and  the  plantain. 


Minnesota  Plant  Life.  471 

The  prairie.  A  most  characteristic  xerophytic  formation  in 
Minnesota  is  the  prairie — especially  the  high  rolling  prairie, 
which  differs  considerably  from  ordinary  meadow  or  pasture. 
Much  of  the  level  prairie  is  mesophytic  rather  than  xero- 
phytic. Here  a  variety  of  grasses,  pulses  and  composites  grow 
luxuriantly.  Such  a  region  is  the  home  of  tumbleweeds,  com- 
pass-plants and  prairie  turf-building  varieties.  Some  strongly 
xerophytic  lilies,  such  as  the  onions,  are  found  in  profusion 
upon  the  plains.  Over  unbroken  prairie,  between  the  plants 
established  upon  it  there  exists  a  great  competition.  This 
goes  on  not  only  between  the  under-ground  portions,  but  also 


FIG.  232. — The  valley  of  the  Minnesota  river  in  the  prairie  district.    Abundant  grass  vegetation. 
After  photograph  by  Professor  R.  D.  Irving. 

between  the  erect  structures.  Thus,  some  prairie  plants  grow 
tall  and  strong  in  order  to  get  the  light  that  they  require.  Sun- 
flowers, indeed,  may  be  regarded  as  the  kings  of  the  prairie. 
Their  erect,  vigorous,  annual  stems  are  like  trees  as  compared 
with  the  more  humble  grasses,  and  where  they  occur  in  abun- 
dance they  may,  to  the  seeing  eye,  be  regarded,  perhaps,  as  in- 
dicative of  how  the  forests  of  the  world  will  appear  hundreds 
of  thousands  of  years  in  the  future.  One  may  look  forward 
and  imagine  sunflowers  and  their  kind  grown  taller  and 
stronger,  a  hundred  feet  or  more  in  height,  and  even  able  to 
usurp  the  place  of  the  trees  that  are  now  abundant  in  the  woods. 


472 


Minnesota  Plant  Life. 


A  great  many  prairie  plants  are  annual,  but  some  of  them 
are  shrubby  and  perennial.  The  shrubs  are  for  the  most  part 
low.  This  is  no  doubt  in  response  to  the  moisture-condition, 
because  if  they  were  high  and  loose,  like  the  dogwoods  and 
willows  of  moister  localities,  their  evaporation  would  be  too 
great. 

All  of  the  formations  that  have  been  described  are  distinctly 
xerophytic  and  in  all  of  them  the  moisture-content  of  the  soil 
is  comparatively  small,  while  its  temperature  may  be  high. 

Pine  forests.  At  this  point  it  might  be  well  to  call  atten- 
tion again  to  the  xerophytic  characters  of  coniferous  forests, 
especially  tamarack  and  spruce  swamps,  balsam  thickets,  and 
river-bluff  lines  of  junipers  or  red  cedars.  Probably  the  whole 
pine  forest  may  be  regarded  as  xerophytic.  The  needle-shaped 
leaves  of  the  white  and  red  pines  are  slow  to  transpire  moisture, 
and  the  pine  forests  reach  their  highest  perfection  along  ridges 
equivalent,  in  their  topographical  character,  to  the  ridges  of 
rolling  prairie.  The  moisture-content  of  such  soil  must  be 
below  the  average.  Along  with  the  pines  a  number  of  xero- 
phytic mosses,  such  as  the  hairy-capped  moss,  of  ferns,  such 
as  the  bracken  ferns,  and  of  flowering  plants,  including  the 
wintergreens,  several  heaths,  and  a  variety  of  asters,  are  com- 
mon. In  such  forests  wand  plants  grow  luxuriantly  along  with 
the  shrubby  underbrush. 

Air  plants.  When  growing  upon  a  substratum  in  which 
nutritive  substances  required  by  the  plant  are  lacking  or  small 
in  amount,  the  surrounding  atmosphere  is  drawn  upon  for  the 
food  supply.  Plants  that  habitually  do  this  are  termed  air- 
plants.  The  Spanish  moss,  tree-top  orchids  and  perching  ferns 
of  the  tropics  afford  typical  examples.  In  temperate  regions 
the  perching  vegetation  is  composed  principally  of  lichens, 
mosses,  liverworts  and  algae.  Much  of  the  rock  vegetation 
previously  mentioned  may  also  be  included  in  this  class,  and 
here,  too,  may  be  classified  the  lichens  and  mosses  that  attach 
themselves  to  the  bark  of  trees,  to  fence  rails,  to  the  walls  of 
buildings  or  to  absolutely  arid  soil. 


Chapter  XLIII. 

Halophytes  and  Mesophytes. 

The  adaptational  type  of  vegetation  known  as  salt  vegetation, 
or  the  halophytic  group,  is  very  sparingly  represented  in  Min- 
nesota. It  reaches  its  best  development  in  the  mangrove 
swamps  of  the  seashore,  and  on  salt-impregnated  beaches  or 
marshes  close  to  the  ocean.  A  few  salt  plants  are,  however,  to 
be  found  in  the  state.  In  the  Red  river  valley  they  are  some- 
times most  prolific  upon  saline  or  alkaline  soil.  Here  are  en- 
countered the  sea-blites,  the  glassworts  and  the  Russian  thistle, 
together  with  several  salt-loving  goosefoots,  salt-loving  purs- 
lanes and  grasses.  One  of  the  plantains  is  capable  of  growing 
in  salt  marshes.  The  most  general  character  of  salt  marsh 
vegetation  is  its  sparseness — a  character  presented,  for  example, 
by  a  growth  of  Russian  thistles.  Such  plants  are  usually  some 
distance  apart,  not  close  together  as  in  most  other  formations. 
Salt  plants,  like  many  bog  plants,  are  stamped  with  the  xero- 
phytic  structural  adaptations.  The  succulence  of  the  glass- 
wort  and  the  great  reduction  of  its  leaf  surfaces  is  distinctively 
suggestive  of  the  cactus  type.  The  fleshy  leaves  of  the  goose- 
foots  and  purslanes  call  to  mind  similar  characters  of  rock  or 
desert  succulents.  If  the  body  of  a  glasswort  is  chewed  a 
strong  saline  taste  will  at  once  be  recognized  and  will  serve  to 
demonstrate  that  salts  are  carried  from  the  soil,  where  they 
exist  so  abundantly,  into  the  juices  of  the  plant.  The  typical 
salt-succulents  are  not  ordinarily  armed  with  thorns  or  spines 
as  are  the  typical  desert-succulents.  This  may  be  because  there 
is  not  such  absolute  sparseness  of  vegetation  in  the  general 
locality  and  they  are,  therefore,  not  called  upon  to  bear  the 
brunt  of  attack  by  hungry  animals. 

Succulents  in  general.  At  this  point  it  may  be  desirable  to 
bring  together  for  comparison  the  different  sorts  of  succulent 
plants.  They  may  be  divided  into  two  general  groups,  leaf- 
succulents,  such  as  the  purslanes  and  century-plant,  in  which  the 


474 


Minnesota  Plant  Life. 


leaves  are  the  principal  succulent  organs;  and  stem-succulents, 
such  as  the  cacti,  in  which  the  leaves  are  reduced  to  thorns  and 
the  stems  have  become  fleshy.  Of  adaptational  types  there 
are  the  following:  desert-succulents,  generally  armed  with 
thorns;  rock-succulents,  more  commonly  unarmed;  salt-suc- 
culents, like  the  glassworts,  sometimes  armed;  and  tree-top- 
succulents,  generally  unarmed.  Of  the  latter  group  tropical 
orchids  furnish  illustrations.  Some  of  the  leaf-succulents  de- 
velop their  leaves  in  rosettes  and  belong  also  to  the  class  of 


FIG.  233.    Cottonwood  trees  on  the  Minnesota  river.    After  photograph  by  Williams. 

rosette  vegetation;  the  century-plants,  the  live-forevers,  and 
the  little  hen-and-chickens  are  examples  of  this  group.  The 
tree-top-succulents,  also,  of  the  orchid  family,  to  be  seen  in 
greenhouses,  in  a  number  of  instances  develop  their  leaves  in 
clusters  upon  short  stems.  Other  leaf-succulents,  however, 
have  the  stems  slender  and  branching.  This  is  true  of  the 
purslane,  the  rock  purslane  and  the  Russian  thistle.  Succulents 
may  have  arisen  through  direct  influence  of  the  environment, 
by  the  warming  of  the  soil.  This  would  tend  to  increase  the 


Minnesota  Plant  Life. 


475 


absorptive  power  of  the  roots,  so  that  desert-succulents  in  par- 
ticular might  be  regarded  as  plants  that  in  a  warm  soil  have 
swollen  themselves  full  of  water  and,  during  the  course  of  gen- 
erations, have  adopted  permanently  the  fleshy  structure. 

Mesophytic  vegetation.  A  number  of  other  plant  forma- 
tions remain  to  be  catalogued  under  the  general  head  of  meso- 
phytic  vegetation.  The  term  is  applied  to  those  plants  which 
are  intermediate,  in  their  reaction  to  moisture,  between  hydro- 
phytes and  xerophytes.  The  characteristic  mesophytic  forma- 
tions of  Minnesota  are  the  hardwood  forests,  the  meadows,  the 


FIG.  284. — A  Minnesota  meadow  bordered  by  shrubbery  and  deciduous  forest.     After  photograph 

by  Mr.  W.  A.  Wheeler. 

cultivated  fields  and  gardens,  the  roadsides  and  the  mesophytic 
shrub,  such  as  underbrush  at  the  edges  of  forests,  or  the  widely 
distributed  scrub,  composed  of  little  oaks,  sumacs  and  maples. 
In  all  these  formations  the  plant-covering  is  thick  and  a  large 
number  of  perennial  species  exist. 

Meadows.  Meadows  or  pastures  are  composed  for  the  most 
part  of  grasses  and  accessory  herbs,  such  as  verbenas,  flax,  sor- 
rels, buttercups,  anemones  and  thistles.  Here,  too,  gentians 
and  speedwells  will  be  found,  together  with  primroses  and 


Minnesota  Plant  Life. 

thoroughworts.  Occasional  xerophytic  plants  enter  such 
meadows  and  one  may  find  in  them  mulleins  or  scouring-rushes 
growing  among  the  typical  mesophytic  grasses  and  herbs.  In 
such  localities  plants  of  xerophytic  tendencies  may  often  be 
distinguished  by  their  rosettes  of  leaves.  In  the  meadows 
mosses  and  sometimes  ferns  occur.  With  the  meadows  should 
be  compared  the  broad  expanses  of  mesophytic  prairie,  es- 
pecially those  of  the  Red  river  valley  and  the  Minnesota. 

Cultivated  fields.  Cultivated  fields  and  gardens,  where  the 
soil  is  stirred  by  the  plow  or  spade,  come  to  be  occupied  by  a 
group  of  vegetation  classified  by  the  farmer  as  crop  and  weeds. 
This  is,  of  course,  a  purely  economic  classification,  and  to  get 
the  proper  botanical  idea  of  a  cultivated  field  all  thought  of 
human  interest  in  the  kinds  of  plants  that  grow  must  be  elim- 
inated. It  will  then  be  discovered  that  the  field  is  occupied 
by  a  dominant  formation  which  owes  its  selection  and  abun- 
dance to  the  distribution  of  its  seeds  or  fruits  through  human 
agency.  A  number  of  accessory  plants  are  also  developed,  in- 
cluding a  variety  of  common  grasses  and  herbs.  Into  such 
fields  some  xerophytic  forms,  like  the  purslanes,  introduce 
themselves,  but  the  majority  of  the  plants  will  not  show  con- 
spicuously the  xerophytic  adaptations  of  structure  which  have 
been  described ;  that  is,  the  weeds  of  a  cultivated  field  are  not 
predominantly  silky  or  strong-scented,  or  succulent,  or  plants 
with  the  edges  of  their  leaves  rolled  in  together.  In  such 
localities,  rather,  will  be  found  the  thistles,  the  fox-tail  grasses, 
the  oxeye  daisies,  the  amaranths,  pigweeds  and  wild  parsleys, 
together  with  some  kinds  of  buttercups  and  clovers.  Such  a 
field  in  its  general  composition  bears  a  close  resemblance  to 
pastures  or  meadows.  A  particular  kind  of  field  is  produced 
when  the  soil  is  sandy  or  alkaline.  Or,  if  the  soil  is  very  hard, 
composed  of  clay  closely  packed  together,  the  vegetation  cov- 
ering it  will  be  different  from  that  of  ordinary  cultivated  fields. 
Sand-loving  plants  or  mat  plants  will  come  in  and  establish 
themselves  prominently  along  with  carpetweeds,  purslanes, 
thistles  and  wild  lettuce. 

Roadside  vegetation.  With  such  wastes  of  weeds  as  have 
been  described,  roadside  vegetation  may  be  connected  and  the 


Minnesota  Plant  Life. 


477 


strong  resemblance  between  it  and  that  of  a  neglected  field  is 
at  once  apparent. 

Mesophytic  shrub.    Of    mesophytic   vegetation    classes,    in 
which  shrubby  or  woody  plants  are  predominant,  a  number  of 


FIG.  235. — Roadside  vegetation  in  summer.    After  photograph 
by  Williams. 

special    varieties   might    be    described    for    Minnesota.     Here 
would  come  the  oak  scrubs,  the  sumac  and  maple  underbrush, 


1 1 


FIG.  236. — Roadside  vegetation  in  winter,  St.  Anthony  Park.     Oaks, 
sunflowers  and  golden  rods.     After  photograph  by  Williams. 

the  hazel  scrub  which  is  particularly  abundant  in  Minnesota 
and  the  poplar  scrub  in  which  the  dominant  plant  is  the  com- 


478  Minnesota  Plant  Life. 

mon  poplar.  Dogwoods,  roses,  hawthorns,  plums,  ashes  and 
other  shrubs  are  prominent  as  components  of  this  general 
formation.  Along  with  these  go  usually  a  number  of  wand 
plants,  herbs  that  thrust  their  slender  stems  up  between  the 
shrubs,  thus  getting  illumination.  Of  these  the  goldenrods,  the 
willow-herbs,  the  evening-primroses  and  the  asters  are  ex- 
amples. Here,  too,  one  will  find  a  variety  of  climbing  or  twin- 
ing herbs  or  vines,  and  the  wild  beans  and  wild  peanuts,  the 
bindweeds  and  morning-glories,  are  to  be  expected.  The  floor 
of  the  underbrush  will  be  occupied  by  a  number  of  little  grasses 


FIG.  237.— Autumnal  underbrush,  Mississippi  river,  between  Minneapolis 
and  St.  Paul.  Golden  rods,  asters  and  sumac.  After  photograph 
by  Williams. 

and  low  herbs,  some  of  which  may  be  vagrant  xerophytes  with 
the  rosette  habit  of  growth  or  with  other  characters  by  which 
they  can  be  recognized. 

Hardwood  forest.  The  hardwood  forest  of  Minnesota,  espe- 
cially as  developed  along  river  bottoms,  where  it  is  made  up 
of  ashes,  maples,  basswoods,  oaks  and  elms,  furnishes  an  ex- 
ample of  what  is  meant  by  mesophytic  forest.  Upon  sand  bar- 
rens where  the  bur-oak  finds  a  congenial  home  the  conditions 
are  almost  xerophytic  and,  therefore,  oak-barrens  were  men- 
tioned under  a  previous  topic. 


Minnesota  Plant  Life. 


479 


Certain  conditions  of  the  forest  floor  arise,  owing  to  the 
decay  of  the  falling  leaves,  that  make  such  a  region  favor- 
able for  the  development  of  humus  plants,  and  a  num- 
ber of  them  are  likely  to  be  found  there,  as,  for  example, 
the  coralroots,  Indian-pipes  and  wintergreens.  Many  shade 
plants  hide  in  the  dense  woods  and  one  finds,  in  their 
depths,  the  trilliums,  the  jacks-in-the-pulpit,  the  broad-leafed 
asters  and  broad-leafed  gol'denrods,  and  upon  moister  ground, 
the  touch-me-nots,  the  anemones  and  the  clintonias.  In  such 

woods  a  number  of  vines 
have  their  growth,  such  as 
the  wild  grape  and  the 
climbing  bittersweet,  or,  of 
slenderer  habit,  the  hop  and 
the  clematis.  A  character- 
istic of  hardwood  forest  is 
the  remarkable  luxuriance 
with  which  spring  flowers  of 
various  sorts  are  produced. 
Before  the  leaves  have  come 
out  upon  the  trees  the  forest 
floor  is  covered  with  flower- 
ing herbs.  The  autumn 
flowers  of  the  forest  are  not 
so  conspicuous  as  in  the 
prairie  regions,  perhaps  be- 
cause there  is  not  so  much 
possibility  of  attracting  the 
attention  of  insects  at  a  dis- 
tance, owing  to  the  prox- 
imity of  tree  trunks  and  to  the  shadows  thrown  by  the  leaf 
crowns.  In  the  spring,  before  the  leaves  have  appeared,  such 
conditions  are  minimized  and  the  development  of  a  conspicuous 
flower  might  be  of  more  advantage  to  the  plant. 

General  considerations.  It  must  not  be  supposed  that  every 
plant  formation  in  nature  is  purely  hydrophytic,  purely  xero- 
phytic,  or  purely  mesophytic.  On  the  contrary,  mixed  forma- 
tions are  exceedingly  common.  A  little  change  in  the  topo- 
graphical features  of  a  region,  a  difference  in  illumination  or  in 


FIG.  238. — Neglected  corner  in  the  Minneapolis 
manufacturing  district.  Weeds  and  shrub- 
bery. After  photograph  by  Williams. 


480 


Minnesota  Plant  Life. 


exposure  to  wind,  a  slight  modification  of  the  chemical  or  phys- 
ical condition  of  the  soil,  or  any  one  of  innumerable  other  varia- 
tions in  the  surroundings  may  suffice  to  alter  the  vegetation 
which  has  become  established.  Thus,  in  a  well-kept  lawn, 
where  conditions  are  normally  mesophytic,  plantains  and  dande- 
lions— both  of  them  mesophytic  in  structure — will  prob- 
ably be  among  the  most  troublesome  weeds.  But  let  the 
lawn  be  established  on  a  soil  -too  porous  and  easily  dried,  or 
let  the  season  be  below  the  average  in  rainfall,  and  very  promptly 
xerophytic  mat  plants,  such  as  spurges  and  prostrate  verbenas, 
and  xerophytic  grasses,  such  as  the  sand-burs  and  other  similar 


FIG.  239. — Modern  hardwood  forest  of  the  St.  Croix  valley,  near  Osceola.     After  photograph 
by  Professor  W.  R.  Appleby. 

vegetation,  will  begin  to  encroach  upon  the  turf.  Vegetation 
coverings,  wherever  they  are  formed,  are  quite  as  sensitive  to 
changes  in  surrounding  conditions  as  is  a  city  lawn,  and  for 
this  reason  the  infinite  variety  of  woods,  fields,  marshes,  swamps 
and  prairies  has  come  to  exist. 

A  very  broad  classification  of  the  influences  which  affect  plant 
adaptations  is  that  made  by  the  German  authority,  Schimper. 
He  distinguishes  essentially — i,  climate;  2,  substratum,  and  3, 
neighbors.  By  climate  he  means  the  complex  of  atmospheric 
and  cosmic  influences,  including,  for  example,  all  the  influences 
of  solar  light  and  heat  and  those  of  atmospheric  vapor  and  wind. 


Minnesota  Plant  Life. 


481 


By  substratum  he  means  the  soil,  whether  it  be  rich  in  calcium, 
sodium  or  nitrogen.  By  neighbors  he  means  the  surrounding 
plants  and  animals  which  by  their  proximity  affect  the  habits 
or  structures  of  the  plant  in  question.  Thus,  in  accordance 
with  the  origin  of  their  most  characteristic  adaptations,  he 
divides  vegetation  into  three  fundamental  groups,  viz.,  climatic 
formations,  substratum  formations,  and  neighborhoods.  Desert 
plants,  for  instance,  may  be  grouped  among  the  climatic,  salt- 
succulents  among  the  substratum,  and  carnivorous  plants  among 


FIG.  240. —View  of  Fort  Snelling,  showing  midsummer  vegetation.      After  photograph 

by  Williams. 

the  neighborhood  formations.  The  further  extension  of  such 
a  classification  is  perhaps  sufficiently  apparent  without  multi- 
plying examples.  Aquatic  plants  would  form  a  special  class. 

Yet  under  even  so  general  an  analysis  it  must  be  evident  that 
very  many  plants — indeed,  most  of  them — will  appear  in  one 
group  or  another,  as  attention  is  diverted  to  one  or  another 
aspect  of  their  adaptation.  The  tree-top  orchid  as  an  air-plant 
falls  into  the  group  of  climatic  formations,  but  as  a  plant  en- 
abled through  the  cooperation  of  its  root  fungi  to  use  decaying 
32 


482  Minnesota  Plant  Life. 

materials  for  food,  it  comes  within  one  of  the  neighborhood 
formations.  No  adaptational  classifications  that  have  yet  been 
devised  are  altogether  accurate,  but  those  by  Warming  and 
Schimper  are  the  most  practicable. 


Chapter  XLIV. 

Maintenance  of  the  Plant  Individual. 


Like  every  other  living  thing  the  plant  must  maintain  itself 
or  die.  For  different  kinds  of  plants  the  normal  duration  of 
life  may  greatly  vary.  Thus,  the  microscopic  females  of  cer- 
tain orchids,  hidden,  as  they  are,  deep  within  the  rudimentary 
seeds  of  their  species,  may  exist  for  but  a  few  days  or  weeks. 
On  the  other  hand,  in  the  canons  of  the  Sierra  Nevada,  there 
still  stand,  challenging  the  winds  and  the  winters  of  the  cen- 
turies, Sequoia  trees  that  were  saplings  when  the  pyramids  were 
new,  noble  trees  when  Rome  was  in  her  glory,  and  already 
giants  of  the  western  forest  when  Columbus  set  sail  on  an  un- 
known sea. 

Whether  the  life  of  a  plant  be  long  or  short,  it  may  be  de- 
scribed as  arising  and  continuing  through  a  series  of  adjust- 
ments, complex,  subtle,  immemorial,  between  the  forces  and 
the  substances  of  Nature.  The  materials  of  which  the  plant 
is  made  are  certain  ordinary  chemical  elements.  Their  num- 
ber and  their  character  can  be  determined  by  recorded  methods 
of  analysis.  The  energy  manifested  by  the  plant  in  its  assim- 
ilative processes,  in  its  growth,  and  in  its  movements  is  but  a 
transformation  of  the  energy  with  which  it  is  supplied  through 
its  food  arid  through  the  warmth  and  illumination  of  the  sun. 
Yet  it  is  impossible  to  reduce  the  living  plant  to  the  terms 
of  an  equation  in  chemistry  and  mechanics.  That  this  cannot 
be  done  is  because  the  plant  is  really  a  microcosm.  The 
problem  of  its  existence  is  as  difficult  and  as  profound  as  that 
of  the  universe.  There  it  stands  beside  one's  doorstep,  humble, 
passive  and  inarticulate.  Yet  it  responds  to  the  forces  of 
light  and  gravitation  reaching  it  from  the  depths  of  infinite 
space.  It  is  touched  by  terrestrial  dews  and  breeze,  and,  after 
its  fashion,  reacts  to  such  local  stimuli.  It  is  moulded  by  the 
inheritance  which  comes  to  it  through  an  ancestral  line  reach- 


484 


Minnesota  Plant  Life. 


ing  down  the  dim  and  distant  ages  to  the  very  moment  when 
the  first  living  particle  appeared  on  the  surface  of  the  earth. 
Thus,  the  child  of  two  infinities,  it  baffles  interpretation ;  for  in 
the  heart  of  every  flower  is  the  riddle  of  the  Sphinx. 

From  such  a  conception  the  poet  may  derive  his  inspira- 
tion and  the  moralist  may  instill  his  lesson.  But  it  is  the  duty 
of  the  student  of  science  to  put  aside  all  feelings  either  of  ex- 
altation or  depression  and  to  endeavor  to  collect  such  facts  as 
are  attainable,  even  when  he  recognizes  that  ultimate  explana- 
tions lie  far  too  deep  to  be  reached  by  the  plummet  of  human 
thought.  In  such  a  spirit  the  plant  has  been  questioned  by 
modern  science  and  somewhat  is  known  of  the  story  of  its  life. 
In  very  simple  fashion  I  shall  endeavor  to  picture  it  as  an 
organism  at  work. 

Living  substance.  The  essential  groundwork  of  every  living 
organism  is  a  material  known  as  living  substance,  or  protoplasm. 
By  no  means  all  portions  of  an  organism  actually  consist  of 
this  living  substance,  although  all  portions  have  arisen  through 
its  activity.  It  is  as  the  spiders  spin  their  webs,  or  as  men 
build  their  cities.  The  living  substance  is  the  organizing  body 
and  the  completed  plant  or  animal  is  the  resultant  organiza- 
tion. As  long  as  the  organism  contains  this  living  substance 
it  may  be  said  to  be  alive;  but  when  the  living  substance  is 
destroyed  throughout  its  body  the  organism  is  then  said  to 
be  dead.  No  longer  held  together  by  the  forces  inherent  in 
its  builder  it  may  be  resolved  again  into  the  elemental  sub- 
stances from  which  it  was  constructed.  Just  so,  to  continue 
the  illustration,  will  a  city,  if  abandoned  by  its  inhabitants, 
fall  into  ruins  and  finally  crumble  into  dust. 

Death  of  an  organism  may  be  sudden  or  gradual.  Thus 
by  fire,  for  example,  a  plant  or  animal  may  in  a  few  moments 
be  converted  from  a  living  being  into  a  handful  of  ashes  and  a 
wreath  of  smoke.  Again,  death  may  be  slow,  creeping  from 
organ  to  organ,  and  even  when  the  organism  as  a  whole  is  no 
longer  living  there  may  in  some  of  its  tissues  still  remain  por- 
tions of  the  living  substance.  The  whelming  of  Pompeii  by 
the  fires  of  Vesuvius  might  be  taken  as  an  illustration  of  the 
first  condition  and  the  gradual  but  relentless  march  of  a  pesti- 
lence might  illustrate  the  other. 


Minnesota  Plant  Life.  485 

Since  plants  have  no  nerves  by  which  shocks  are  transmitted 
to  a  central  system  and  thence  to  every  portion  of  the  body, 
they  die  much  more  slowly  than  do  animals. 

Location  of  the  living  substance.  Only  in  very  lowly  crea- 
tures, such  as  the  slime-moulds,  does  the  greater  part  of  the 
body  consist  of  living  substance.  The  jelly-like  masses  de- 
scribed for  such  organisms  are  among  the  best  examples  of 
pure  protoplasm.  Generally  the  body  of  the  plant  consists, 
for  the  most  part,  of  wood,  bark,  cellulose,  starch,  oils,  water, 
sugar,  ash  and  a  great  variety  of  other  compounds  manufac- 
tured at  different  times  by  the  living  substance.  One  exam- 
ining a  tree  or  herb  in  the  ordinary  way  can  neither  see  nor 
touch  any  of  the  living  substance,  whatever,  but  must  lay  his 
hand  upon  leaf-skin,  cork  or  some  of  the  various  other  periph- 
eral materials  of  the  plant.  It  is  not  otherwise  if  an  animal 
be  investigated  in  like  superficial  manner.  The  living  sub- 
stance lies  concealed  within  the  walls  of  the  city  it  has  built. 
To  see  it  and  to  study  it  most  delicate  manipulation  is  neces- 
sary. 

Certain  portions  of  plants  are  transparent  and  at  the  same 
time  contain  living  substance.  Such  areas  are  favorable  for 
observation.  If,  for  example,  some  of  the  hairs  that  grow 
along  the  stem  of  a  tomato-vine  are  carefully  removed,  placed 
in  a  drop  of  water  and  examined  under  a  sufficiently  powerful 
microscope,  it  will  be  discovered  that  they  are  composed  of 
cylindrical  joints.  Each  joint  has  a  \vall  transparent  as  glass, 
and,  within,  most  of  the  interior  is  occupied  by  water.  There 
is  also  present,  however,  a  pellucid  slime,  very  conspicuous 
when  once  identified.  It  keeps  up  a  remarkable  streaming 
motion  and  tiny  granules  in  it  are  carried  along  like  boats  in 
a  rapid  current.  The  direction  of  the  stream  changes  from 
time  to  time.  Eddies  form  in  the  current.  Sometimes  the 
streams  flow  together  from  different  parts  of  the  cell  interior 
and  a  mound  of  slime  is  formed.  Sometimes  the  streams  fork 
again  and  again,  making  a  network  within  the  cell.  The  mo- 
tion may  cease  if  the  temperature  is  lowered  or  raised  beyond 
certain  limits.  It  ceases,  also,  if  the  cell  becomes  dry  or  if  it 
is  exposed  to  the  vapors  of  ether  or  chloroform.  A  slight 
electric  shock  stops  the  movement,  but  after  a  time  it  may 


486  Minnesota  Plant  Life. 

beg-in  again.     A  strong  electric  shock  stops  it  forever.     This 
streaming,  pellucid  slime  is  the  living  substance. 

Not  only  in  hair-cells  does  the  living  substance  commonly 
occur,  but  in  many  other  portions  of  the  plant.  It  is  found 
at  the  tips  of  all  young  roots  and  buds.  In  the  green  cells  of 
leaves  it  is  always  present.  It  will  be  found  in  certain  of  the 
conducting-areas  of  the  plant — in  the  leaf  network  and  in  the 
young  fibers  of  the  stem.  In  trees  and  shrubs  it  occurs  neither 
in  the  mature  bark  nor  in  the  mature  wood  of  the  trunk, 
branches  or  woody  roots.  Between  the  bark  and  wood  there 
exists,  however,  in  ordinary  trees  a  thin  layer — no  thicker,  in- 
deed, than  tissue  paper — known  as  the  cambium.  In  this  layer 
of  cells  the  living  substance  will  be  found.  It  occurs  in  all 
spores,  eggs  and  spermatozoids,  in  all  very  young  organs  and 
tissues,  and  in  general  in  all  growing  parts  of  the  plant. 

Physical  structure  of  the  living  substance.  Years  ago  when 
investigation  of  the  living  substance  was  in  its  infancy  it  used 
to  be  described  as  a  "structureless  slime"  or  as  "living  jelly"- 
these  phrases  indicating  how  little  was  really  known  of  its  or- 
ganization. The  researches,  however,  of  the  last  fifteen  years 
in  particular,  have  revealed  that  the  intimate  structure  of  the 
living  substance  is  extremely  complex — so  much  so,  indeed, 
that  a  new  science,  the  science  of  the  cell,  has  developed,  until 
to-day  libraries  can  be  collected  in  this  field  alone.  It  would 
appear  that,  just  as  the  body  of  a  plant  or  animal  is  composed 
of  cells  and  their  products,  so  the  particle  of  living  substance 
in  each  active  cell  is  itself  composed  of  smaller  bodies  and  their 
products,  the  whole  constituting  an  organism  of  extreme  com- 
plexity. It  may  properly  be  said  that  there  are  now  known 
three  hierarchies  of  life — social  life,  individual  life,  and  cell 
life.  In  the  first  of  these  man  has  his  place  as  a  component 
body,  in  the  second  he  exists  as  a  self-sustained  individual,  while 
in  the  third  lies  the  living  basis  of  his  organization. 

Modern  research  has  shown  that  the  motion  seen  in  a  living 
cell  lying  under  the  microscope  of  the  observer  is  by  no  means 
disorderly  or  unrelated.  On  the  contrary  the  kaleidoscopic 
changes  in  the  living  substance  are  now  known  to  have  pro- 
found significance  in  nutrition,  growth  and  heredity.  The  dif- 
ference between  the  old  idea  and  the  new  may  be  suggested  by 


Minnesota  Plant  Life.  487 

an  illustration.  Suppose  some  observer  stationed  in  an  air- 
ship many  miles  above  the  battle-field  of  Waterloo.  Per- 
haps by  the  use  of  powerful  glasses  he  could  have  made  out  a 
vague  commotion  far  below  him,  but  he  could  scarcely  have 
distinguished  what  actually  was  happening.  To  an  observer 
on  the  hills  near  by,  the  battle  would  have  presented  a  very 
different  meaning.  Thus,  the  earlier  students  of  living  sub- 
stance, because  they  could  not  see  all  that  is  revealed  to  the 
observer  of  to-day,  fell  into  the  error  of  thinking  that  they  had 
under  their  microscopes  a  "structureless  slime." 

Living  substance  is  by  no  means  homogeneous.  Sometimes 
it  shows  a  fibrous  structure  made  up  of  innumerable  meshes 
and  threads.  Again  it  appears  as  a  foam  or  emulsion  consisting 
of  an  intricate  combination  of  larger  and  smaller  bubbles.  At 
one  time,  when  more  saturated  with  water,  it  is  liquid,  plastic 
and  mobile.  At  another,  when  like  a  sponge  it  has  expelled  a 
portion  of  its  moisture,  it  seems  almost  solid  and  is  passive 
and  immobile.  Thus  the  living  substance  in  the  active  cells  of 
a  growing  hair  and  in  the  dormant  cells  of  an  ungerminated 
seed  may  seem  very  different.  By  the  absorption  or  expul- 
sion of  water  living  substances  may  pass  from  one  condition  to 
the  other. 

Chemical  composition  of  living  substance.  The  following 
chemical  elements  are  components  of  living  substance :  carbon, 
oxygen,  hydrogen,  nitrogen,  sulphur  and  phosphorus.  In  the 
higher  plants  the  following  metals  are  also  necessary  for  the 
formation  of  living  substance,  although  they  do  not  become 
essential  components  of  protoplasm :  iron,  potassium,  mag- 
nesium and  calcium.  Numerous  other  elemental  substances, 
such  as  sodium,  lithium,  manganese,  silicon,  chlorine,  bromine, 
and  iodine  are  frequently  found  in  the  bodies  of  plants;  but 
they  do  not  appear  to  be  everywhere  either  essential  compon- 
ents of  the  living  substance  or  necessary  reagents  for  its  con- 
struction. 

It  must  not  be  supposed  that  all  living  substance  is  of  exactly 
the  same  chemical  composition.  To  say  that  no  two  particles 
are  precisely  alike  would  probably  be  nearer  the  truth.  Al- 
though the  number  of  the  essential  elementary  components  is 
so  small,  many  atoms  of  each  kind  are  present  and  the  varia- 


488  Minnesota  Plant  Life. 

tions  in  their  relative  positions  and  combinations  might  be  al- 
most infinite.  Certainly,  however,  the  difference  between  one 
piece  of  living  substance,  such  as  the  egg  of  a  fish,  and  another, 
such  as  the  egg  of  a  fern,  consists  less  in  chemical  composition 
than  in  physical  structure.  Chemically,  all  living  substance  lies 
within  limits  which  have  been  just  outlined. 

Physiological  character  of  living  substance.  The  following 
are  the  most  important  physiological  characters  of  protoplasm : 
i.  Assimilation,  the  power  of  initiating  and  maintaining  com- 
plex chemical  changes  by  which  not-living  matter  is  brought 
into  the  living  condition  and  into  relation  with  the  living  sub- 
stance. 2.  Grozvth,  a  term  here  applied  to  the  increase  of  living 
substance  in  mass.  3.  Irritability,  the  quality  of  responding, 
after  a  manner  determined  by  heredity,  to  impulses  originating 
within  or  without  the  body.  4.  Reproduction,  the  power  of 
separating,  from  the  body,  portions  of  living  substance  that, 
under  the  influence  of  heredity,  may  recapitulate  the  develop- 
mental stages  of  the  parent.  Together  with  assimilation,  in  its 
broad  sense,  goes  on  a  variety  of  chemical  processes.  By  these, 
waste  products  are  formed  and  excreted,  accessory  products 
are  combined  and  modified,  and  a  variety  of  complex  substances 
are  broken  down  into  simpler  forms,  thus  liberating  energy  that 
is  either  used  in  growth  and  movement  or  reappears  as  body- 
temperature,  phosphorescence,  electrical  disturbances  or  some 
form  of  mechanical  work. 

Requisitions  made  by  living  substance  on  its  environment. 
In  order  to  maintain  its  physiological  processes,  living  sub- 
stance must  have  a  supply  of  matter  and  a  supply  of  energy. 
The  supply  of  matter,  or  the  food  of  the  organism,  may  be  of 
great  variety,  provided  that  it  contain  the  necessary  chemical 
elements  in  assimilable  form.  The  great  primal  source  of 
energy  is  the  sun  and  upon  its  light  and  heat  all  living  things, 
in  the  final  analysis,  will  be  found  depending.  Some,  however, 
like  the  fungi  and  the  animals  receive  much  of  this  energy  indi- 
rectly. It  is  utilized  directly  by  the  green  plants,  the  color  of 
which  indicates  the  presence  in  their  tissues  of  that  extraordi- 
nary accessory  product  of  living  substance — leaf-green,  or  chlor- 
ophyll. This  leaf-green  that  stains  either  the  entire  living  sub- 
stance of  the  cells  that  are  set  aside  for  starch-making,  or  cer- 


Minnesota  Plant  Life.  489 

tain  specialized  portions,  is  a  form  of  "light-engine"  by  which 
the  energy  of  the  sunlight  is  set  at  work  building  up  starch 
out  of  such  simpler  substances  as  carbonic-acid  gas  and  water. 

The  food  of  plants.  In  general  the  diet  upon  which  a  plant 
can  live  is  simpler  than  that  necessary  for  an  animal.  The 
important  elements  are  principally  obtained  from  sources  as 
follows :  Carbon  is  collected  from  the  carbonic-acid  gas  of  the 
atmosphere ;  oxygen  both  from  the  atmosphere  and  from  water ; 
nitrogen  from  salts  in  the  soil,  but  not  from  the  atmosphere; 
and  hydrogen  from  water.  Sulphur,  phosphorus  and  the 
metals  are  obtained  from  soluble  salts  in  the  soil.  In  excep- 
tional instances  the  sources  may  be  other  compounds  than  those 
mentioned.  Thus  nitrogen  and  possibly  hydrogen  may  be 
taken  from  ammonia  products,  but  this  would  be  very  unusual. 
What  has  been  stated  refers  to  green  plants  alone,  for  plants 
without  leaf-green  demand  a  much  more  complex  diet.  Their 
carbon  they  may  obtain  from  sugars  and  from  proteids;  their 
nitrogen  from  proteids ;  their  oxygen  and  hydrogen  from  water, 
from  sugars  or  from  proteids;  their  sulphur  and  phosphorus 
from  the  soil,  or  perhaps  from  proteids ;  and  their  metallic  sub- 
stances from  soluble  salts  in  their  substratum. 

The  plant  does  not  ingest  solid  particles  of  food  as  does  the 
animal — though  to  this  certain  carnivorous  plants  are  quasi  ex- 
ceptions— but  receives  its  nutriment  either  as  gases,  liquids  or 
solutions.  The  absorptive  tract  of  the  plant  is  often  specialized 
so  that  one  area  is  fitted  better  for  absorption  of  gases  and 
another  for  absorption  of  liquid  solutions.  Thus  in  the  ordi- 
nary green  plant  it  is  the  foliage  that  characteristically  absorbs 
carbonic-acid  gas  and  oxygen,  while  the  root-system  absorbs 
water  with  nitrogen  compounds  and  metallic  salts  in  solution. 
Aquatic  plants  are  more  generalized,  as  are  also  air-plants — 
although  the  latter  use  their  exposed  root-system  very  much 
as  if  established  on  a  firm  soil.  Humus  plants  and  parasites 
obtain  their  food  from  the  bodies  of  other  plants  or  animals 
or  from  decaying  organic  substances. 

Partnerships  for  obtaining  food.  Some  extraordinary  part- 
nership arrangements  for  securing  food  have  been  developed 
in  the  plant  world.  Thus,  in  the  lichen-body  a  fungus  and  an 
alga  live  in  partnership  and  obtain  their  food  quite  as  if  they 


490  Minnesota  Plant  Life. 

constituted  an  independent  green  organism.  So,  too,  do  many 
humus  plants,  such  as  coralroots  and  pine-saps,  depend  upon 
the  presence,  in  their  underground  portions,  of  root-fungi.  By 
aid  of  these  they  can  secure  from  the  soil  organic  substances 
that  alone  they  could  not  collect.  In  return  for  such  service 
they  harbor  the  fungus  in  their  tissues. 

Intra-specific  partnerships.  Among  higher  plants  a  remark- 
able division  of  labor  exists.  By  it  the  spore-bearing  plants  of 
the  species  exist  as  the  primary  food-gatherers,  while  the  egg- 
producing  and  sperm-producing  plants  live  dependently  upon 
them,  having  no  original  food-collecting  capacity  of  their  own. 
Thus,  among  flowering  plants  the  female,  quite  devoid  of  leaf- 
green,  lives  upon  substances  stored  up  for  her  use  in  the  rudi- 
mentary seed  borne  by  the  spore-producing  plant.  The 
male,  also,  among  flowering  plants,  lives  parasitically  upon  the 
tissues  of  the  immature  seed  or  fruit.  Similar  conditions  are 
known  to  exist  among  certain  ferns  and  club-mosses.  Other 
highly  interesting  inter-relations  for  nutrition  are  those  between 
the  mother  plant  and  the  offspring,  as  in  cone-bearing  trees; 
or  between  the  twin  embryos  in  seeds  of  higher  flowering  plants. 
In  the  latter  instance  one  of  the  twins  customarily  gorges  itself 
with  food  for  the  benefit  of  the  other,  and  by  the  latter  it  is 
ultimately  devoured.  In  such  a  life-history  as  that  of  the  sun- 
flower, for  example,  only  the  ordinary  green  leaf-bearing  plant 
of  the  species  is  an  independent  collector  of  food.  Upon  it 
depend  the  male  and  female  plants,  the  albumen-plant  of  the 
seed,  and,  for  a  time,  the  embryo-plant  that  is  later  to  develop 
into  a  new  leaf-bearing  individual. 

Storage  of  food.  After  absorbing  its  food  materials  from 
the  air,  soil,  water  or  bodies  of  other  organisms,  these  are  re- 
combined  by  the  plant  into  characteristic  products.  In  green 
plants  the  first  visible  product  of  assimilation  is  starch.  This 
substance  originates  in  the  leaves  and  other  green  portions 
under  the  influence  of  sunlight.  It  arises  as  little  white  gran- 
ules. These  may  grow  to  a  considerable  size,  but  are  ordi- 
narily attacked  by  ferments,  converted  into  soluble  sugars  and 
conveyed  along  the  conduction-paths  of  the  plant  either  to 
growing  areas  where  they  are  used  in  construction,  or  to  storage 
areas,  such  as  bulbs,  tubers,  fleshy  roots,  seed-albumen  or  bud- 


Minnesota  Plant  Life.  491 

cores  in  which  they  are  deposited  as  starch  or  as  oils.  Proteid 
substances,  originating  also  in  the  foliage  of  the  green  plant, 
may  be  carried  away  in  the  form  of  peptones  to  growing  tracts, 
or  to  storage  organs,  where  they  may  take  the  shape  of  little 
granules,  known  as  farina  grains  or  aleurone  grains.  Storage 
layers  commonly  occur  along  the  conduction-paths,  while  spe- 
cial storage  organs  are  produced  in  a  variety  of  plants.  Of 
such  storage  organs  an  ordinary  potato,  onion,  beet  or  carrot 
may  serve  as  familiar  examples. 

Ultimate  disposal  of  the  food.  The  materials  taken  into  the 
body  of  the  plant  and  subjected  to  the  elaborative  processes 
initiated  by  the  living  substances  must  be  either  retained  as 
part  of  the  body  or  excreted.  The  high  manifestation  of  energy 
that  characterizes  the  animal  is  by  no  means  so  characteristic 
of  the  plant.  In  other  words,  constructive  processes  prepon- 
derate in  the  plant-\vorld  and  a  greater  proportion  of  material 
received  as  food  remains  in  the  body  of  the  plant  than  in  the 
body  of  the  animal.  Excrements  are,  therefore,  not  so  abun- 
dant among  plants  as  among  animals.  Indeed  the  principal 
plant  excreta  are  gaseous.  From  the  leaves  are  given  off 
oxygen,  a  waste-product  of  starch-making,  and  water  vapor. 
Water  in  the  fluid  state  is  also  rejected  by  many  plants.  Car- 
bonic-acid gas,  a  waste-product  of  respiration,  is  excreted  from 
the  surface  of  the  plant,  both  in  the  area  of  the  shoot  and  of 
the  root.  Solid  excreta,  however,  are  not  formed  by  plants. 

When  retained  in  the  body  of  the  plant,  food  materials  may 
assume  a  great  variety  of  forms.  A  certain  portion  is  utilized 
in  the  production  of  new  living  substance,  but  by  far  the  greater 
.amount  is  stored  as  cellulose,  bark-substance,  wood-substance, 
gelatine,  crystals,  organic  acids,  coloring  material,  tannin,  alka- 
loids, glucosides,  oils,  fats,  resins,  gums,  reserve-food  and  cell 
sap.  Many  thousands  of  plant  products  are  known,  so  marvel- 
ous is  the  chemical  activity  of  the  living  substance. 

Growth.  The  term  growth  is  rather  an  ambiguous  one,  since 
it  is  applied  in  several  different  ways.  It  should  at  least  ex- 
clude nutrition,  and  should  generally  indicate  increase  in  size. 
Sometimes,  however,  there  may  be  an  increase  in  mass  without 
a  visible  increase  in  size,  and  it  seems  difficult  in  such  an  in- 
stance not  to  apply  the  term  growth  to  the  process  of  enlarge- 


492  Minnesota  Plant  Life, 

ment.  For  the  sake  of  clearness  at  least  three  types  of  growth 
should  be  distinguished:  i,  growth  of  living  substance;  2, 
growth  of  cells,  and  3,  growth  of  tissues  and  organs.  The  first 
takes  place  as  a  result  of  constructive  assimilative  processes, 
and  may  or  may  not  be  accompanied  by  a  visible  increase  in 
size.  The  second  may  go  on  without  increase  in  mass  either 
of  the  living  substance  or  of  the  organ  to  which  the  growing 
cell  belongs.  The  third  may  occur  while  mass  of  living  sub- 
stance and  cells  are  increasing,  but  sometimes  even  while  mass 
is  stationary  or  diminishing.  Thus  by  change  in  shape  of  its 
component  cells  an  organ  may  elongate,  though  while  it  does 
this  there  may  be  no  actual  increase  in  substance.  Neverthe- 
less such  an  elongation  might  appear  as  visible  growth.  Such 
an  analysis  is  somewhat  disregardful  of  refined  and  technical 
terminology,  but  is  not  seriously  at  variance  with  the  truth. 

Growth  of  living  substance.  The  most  important  fact  to  be 
kept  in  mind  concerning  the  growth  of  living  substance,  is  that 
it  is  not  simply  an  accretion  of  new  material.  Growth  goes 
on  in  varying  degree  among  the  innumerable  component  parts 
of  the  living  substance,  each  growing  in  its  own  way  and  at 
its  own  rate.  Thus  results  the  growth  in  aggregate  of  the 
whole.  To  illustrate  this,  let  there  be  imagined  a  village  full 
of  children.  After  a  year  or  two  had  passed  the  children 
would  have  grown  and  the  total  human  weight  of  the  village 
would  have  increased.  Some,  however,  of  the  children  would 
have  grown  more  than  others, — some,  even,  might  not  have 
grown  at  all.  The  final  result,  however,  a  general  increase  in 
weight,  was  not  obtained  by  mere  accretion.  In  such  fashion 
does  a  microscopic  piece  of  living  substance  grow.  It  grows 
as  an  organism,  not  as  an  office-building  nor  as  a  snow-drift. 

For  living  substance,  the  limits  of  growth  above  which  me- 
chanical support,  such  as  partition  walls,  strengthening  beams, 
and  retaining  membranes,  becomes  desirable,  are  generally  be- 
low the  limits  of  unaided  vision.  For  this  reason  most  plant 
cells  are  of  microscopic  size.  The  cell  may,  in  a  complex 
tissue  or  organ  composed  perhaps  of  millions,  be  regarded  as 
resulting  from  the  necessity  of  individualizing  small  pieces  of 
living  substance.  It  is  true,  cells  vary  greatly  in  size.  The 
smallest  are  those  of  the  bacteria.  The  largest  are  those  of 


Minnesota  Plant  Life.  493 

certain  oceanic  relatives  of  the  green  felt — an  alga  belonging 
to  the  bright-green  group.  Yet  even  in  the  latter,  the  body, 
as  large  as  a  hen's  egg,  which  exists  without  partition  walls 
cutting  it  in  all  the  planes  of  space  is  equivalent  rather  to  a 
cell-aggregate  than  to  a  single  cell. 

Just  why  the  limits  between  which  cells  vary  in  size  should 
be  what  they  are,  is  a  difficult  question  to  answer.  The  cause 
must  be  sought  in  the  structure  and  qualities  of  the  living  sub- 
stance and  in  the  conditions  of  the  outer  world  as  they  react 
upon  it.  A  proper  comparison  would  be  with  the  towns  and 
cities  of  the  human  species.  These  vary  in  size  between  mere 
hamlets  to  cities  like  London,  Paris  and  New  York.  Cities 
with  fifty  million  inhabitants,  however,  do  not  exist,  because 
with  human  society  organized  as  it  is  they  cannot  be  main- 
tained. To  explain  exactly  the  causes  that  have  fixed  6,000,- 
ooo  rather  than  some  other  number  as  a  population  limit  be- 
yond which  human  cities  have  not  yet  developed,  would  re- 
quire a  more  exhaustive  knowledge  of  anthropology  and  soci- 
ology than  any  one  possesses.  Still  more  impossible  is  it  to 
state  why  the  limits  of  cell  size  are  precisely  what  they  are.  It 
is,  at  the  same  time,  clear  that,  as  in  the  instance  of  the  cities, 
the  reason  lies  essentially  in  the  nature  of  the  organism — that 
is,  the  living  substance  which  builds  the  cell. 

The  largest  masses  of  living  substance  in  which  cell  com- 
partments have  not  appeared  are  the  jelly-like  bodies  of  the 
slime-moulds.  These  aggregates  of  protoplasm,  in  patches 
the  size  of  a  dinner  plate,  are  sometimes  found  on  decaying 
timber.  Because  they  are  not  provided  with  internal  mechan- 
ical support  they  lie  flat  and  shapeless  upon  their  substratum. 

Origin  of  the  cell  as  a  structural  unit.  One  is  now  in  a 
position  to  understand  why  living  substance  almost  universally 
displays  itself  in  the  microscopic  individualized  portions  known 
as  cells.  The  cell  is  an  adaptation  fitted  to  enable  the  living 
substance,  under  the  stress  of  outward  conditions,  to  perform 
its  physiological  functions  in  a  better  way  than  if  this  adapta- 
tion had  not  been  called  into  being.  There  is  reason  to  sup- 
pose that  mechanical  support  and  protection  against  shock 
might  have  been  the  principal  necessities  under  which  primal 
masses  of  living  substance  came  to  develop  the  cell-habit.  In 


494  Minnesota  Plant  Life, 

both  plants  and  animals  cell  structure  is  almost  universal  and 
both  kinds  of  creatures  are  said  to  be  composed  of  cells.  It 
must  be  observed,  however,  that  the  cells  are  not  the  funda- 
mental units  of  structure,  but  are  themselves  individualized 
areas  arising  through  adaptation  of  the  living  substance  to  its 
surroundings. 

The  growth  of  cells.  Certain  distinctions  appear  to  exist 
between  the  growth  of  cells  and  the  growth  of  living  substance. 
When  the  living  substance  grows  there  is  an  actual  increase 
in  its  mass.  A  cell,  however,  may  grow  by  distending  itself 
with  water  and  there  need  be  no  absolute  increase  in  its  liv- 
ing substance.  A  typical  cell  shows  a  delicate  wall  surround- 
ing the  living  substance,  and  a  portion  of  the  latter  is  differ- 
entiated from  the  rest  as  a  complex  body  termed  the  nucleus. 
Within  the  meshes  of  the  living  substance  cell  sap  occurs.  A 
normal  condition  of  such  a  cell  is  the  plump,  water-swollen, 
elastic  state  known  as  turgor.  If  enough  of  the  cell  sap  is  lost 
by  evaporation  through  the  delicate  wall,  the  turgid  condition 
is  no  longer  maintained  and  the  cell  becomes  limp  and  flabby. 
An  organ  composed  of  cells, — as  for  example,  a  leaf, — when  the 
cells  have  lost  their  turgidity  through  evaporation,  becomes 
wilted.  In  such  a  condition  cell  growth  cannot  go  on,  and 
it  may  be  stated  categorically  that  for  the  growth  of  cells  turgor 
is  a  prerequisite. 

Maintenance  of  turgor.  In  order  to  understand  how  turgidity 
of  a  cell  is  established  and  maintained,  the  common  physical 
phenomenon  of  liquid  dialyzing  through  a  membrane  must  be 
thoroughly  understood.  The  living  substance  of  a  cell,  having 
an  avidity  for  water,  will  readily  absorb  it  if  it  can  be  obtained. 
Since,  however,  having  adopted  the  cell-habit,  each  particle  of 
living  substance  is  surrounded  by  a  continuous  membrane  or  cell 
wall,  the  liquid,  to  reach  the  interior,  must  filter  through  this 
membrane.  It  is  a  fact  of  observation  that  certain  liquids  or 
solutions  pass  through  membranes  much  more  readily  than  do 
others.  Thus,  if  a  bladder  be  filled  with  brine  and  placed  in  a 
tub  of  fresh  water  it  will  soon  become  swollen,  because  the 
fresh  water  passes  inward  more  rapidly  than  the  salt  water 
passes  outward.  If,  however,  a  bladder,  distended  with  fresh 
water  should  be  placed  in  a  tub  of  brine  the  reverse  action 


Minnesota  Plant  Life.  495 

would  take  place  and  the  bladder  would  become  limp.  If,  fur- 
ther, syrup  were  placed  in  the  bladder  and  brine  around  it,  the 
first  instance  would  be  repeated  and  the  bladder  would  become 
swollen.  Such  observations  indicate  that  syrup  passes  more 
slowly  through  the  membrane  than  does  brine.  In  general  it 
may  be  said  that  solutions  of  relatively  complex  chemical  sub- 
stances move  through  membranes  more  slowly  than  do  solu- 
tions of  relatively  simple  substances.  The  phenomenon  of 
dialysis  through  a  membrane  is  termed  osmose. 

Living  cells,  since  they  are  provided  with  cell  sap  and  mem- 
branes, are  in  a  condition  to  maintain  osmotic  relations  either 
with  neighboring  cells  or  with  any  moisture-containing  medium 
that  surrounds  them.  The  presence  or  absence  of  osmotically 
active  compounds  dissolved  in  the  cell  sap  has  much  to  do 
with  the  regulation  of  turgor,  as  it  has  also  with  the  conduc- 
tion of  food-solutions  from  one  part  of  an  organ  to  another. 
Thus,  not  only  are  the  various  cells  of  a  root-surface  kept  turgid 
by  the  maintenance  of  an  inward  flow  of  liquid  from  the  soil, 
but  compounds  such  as  soluble  salts  of  nitrogen  or  of  metals 
are  transported — along  special  paths  in  the  higher  plants — until 
they  reach,  perhaps,  a  starch-making  and  proteid-making  organ 
such  as  the  leaf.  Not  only  is  this  upward  flow  of  crude  food 
solutions  normal  for  the  higher  green  plants,  but  simultane- 
ously there  is,  of  refined  food-products,  such  as  sugar  and  pep- 
tones, a  downward  flow  from  the  leaves  to  other  parts  of  the 
plant,  even  to  the  most  distant  rootlets. 

A  growing  cell  may  then,  upon  the  whole,  be  regarded  as  a 
self-inflating  bladder,  which,  through  the  activity  of  the  living 
substance,  absorbs  water  from  its  surroundings.  It  does  this 
by  the  aid  of  osmotically  active  compounds  produced  by  the 
living  substance  and  dissolved  in  the  cell  sap.  In  highly  organ- 
ized plants,  such  as  the  ordinary  trees,  other  factors  besides 
osmose  enter  into  the  ascent  of  the  sap,  but  need  not  here  be  dis- 
cussed. 

Growth  of  tissues  and  organs.  Tissues,  that  is,  structural 
cell-aggregates,  and  organs,  that  is,  physiological  tissue-aggre- 
gates, grow  by  the  growth  of  their  component  cells.  There 
may  be,  however,  cell-growth  without,  in  a  strict  sense,  growth 
of  the  tissue  or  organ.  For  example,  a  nasturtium  leaf-stalk 


496  Minnesota  Plant  Life. 

bends  towards  the  light,  and  there  may  be  enlargement  of  cells 
on  the  convex  side,  or  contraction  of  cells  on  the  concave  side, 
or  both ;  yet  such  a  curvature  should  scarcely  be  called  growth 
of  the  organ.  Growth  of  a  tissue  or  organ  might  perhaps  be 
defined  as  permanent  enlargement  arising  through  growth  of 
the  component  cells. 

There  are  ordinarily  distinguished  three  important  stages  in 
the  growth  of  an  organ.  These  are:  i,  the  stage  of  cell- 
multiplication;  2,  the  stage  of  cell-enlargement;  3,  the  stage 
of  cell-differentiation.  A  mature  organ  commonly  consists  of 
very  many  more  cells  than  would  be  found  in  the  same  organ 
when  immature.  But  since  all  cells  arise  from  preceding  cells 
and  never,  so  far  as  known,  in  any  other  way,  whatever,  it  is 
evident  that  there  must  have  been  a  general  division  of  pre- 
existent  single  cells  into  cell-groups.  This  leads  to  an  inquiry 
into  the  nature  of  organ-rudiments.  It  may  be  stated  broadly 
that  the  rudiment  of  any  plant  organ  is  either  a  single  cell  or  a 
group  of  cells.  The  stems  and  leaves  of  a  moss  or  of  a  liver- 
wort, the  stems  and  roots  of  ferns,  the  spore-cases  of  "true" 
ferns  and,  perhaps,  even  the  stems  of  pine  trees,  are  examples 
of  organs  arising  from  single-celled  rudiments.  Of  organs 
arising  from  groups  of  cells  there  might  be  mentioned  the  roots, 
stems  and  leaves  of  the  higher  seed  plants,  the  spore-cases  of 
club-mosses,  the  spore-cases  of  seed-producing  plants  and,  in 
brief,  organs  generally  in  higher  forms. 

The  tip  of  a  growing  organ  is  commonly  occupied  by  a  little 
group  of  cells  in  process  of  division.  Thus  the  tips  of  roots, 
the  tips  of  buds  inside  the  covering  of  overlapping  scales,  and 
the  tips  of  very  young  leaves,  will  be  found  to  consist  of  small, 
thin-walled  cells,  packed  full  of  living  substance,  and  each 
capable  of  dividing  into  two  cells  by  the  formation  of  partition 
walls.  In  such  rudimentary  areas  the  cells  are  at  first  very 
similar,  but  before  long  some  cells  of  the  mass  begin  to  assume 
shapes  and  structures  that  are  distinctive.  Close  behind  the 
growing  tip  of  a  young  root  the  skin-cells  will  have  begun 
to  flatten  and  the  cells  of  the  central  conduction-path  will  have 
begun  to  elongate.  These  differences  and  many  others  be- 
come progressively  more  marked  and  in  older  parts  of  the 
root  each  tissue — the  skin,  the  wood,  the  pith,  the  reservoir- 


Minnesota  Plant  Life.  497 

tissue,  the  bast,  the  cork,  the  milk  tissue  and  the  skeleton  tissue 
—will  have  become  developed  with  its  own  structural  pecul- 
iarities. 

In  growing  organs  the  cells  live  together  somewhat  after  the 
manner  of  individuals  in  a  community.  They  influence  each 
other  in  a  variety  of  ways — by  mutual  pressure,  by  contact,  by 
transfers  of  solutions,  by  propagation  of  impulses  and  even 
by  direct  interchange  of  living  substance.  In  growing  tips 
the  partitions  between  the  cells  often  have  extremely  minute 
perforations  through  which  the  protoplasm  is  continuous  from 
cell  to  cell.  By  this  continuity  the  tip  remains  an  organic  unit, 
and  every  plant  organ,  from  the  earliest  rudiment,  must  be 
regarded,  not  as  built  up,  cell  upon  cell,  in  the  manner  that 
bricks  are  laid  in  some  edifice  of  human  construction,  but 
rather,  as  an  elaboration  of  living  substance  growing  under  the 
restraints  of  physical  and  chemical  law,  under  the  ever  present 
influences  of  the  surroundings,  and  under  the  hereditary  bonds 
of  the  cell-habit. 

Irritability.  This  term  is  applied  to  that  quality  of  living  sub- 
stance manifested  when,  by  contraction  or  chemical  change,  it 
responds  to  stimulation;  and  when  the  response  is  apparently 
altogether  disproportionate  to  the  stimulating  cause.  Starch- 
making  under  the  influence  of  sunlight  is  not  classified  as  a 
form  of  irritability,  since  it  is  a  reaction  not  particularly  differ- 
ent, in  degree,  from  the  reaction  that  goes  on  when  a  photo- 
graphic plate  is  exposed  to  the  chemical  rays  of  the  sun.  There 
is  here  no  apparent  disproportion  between  cause  and  effect  and 
the  reaction  does  not  essentially  differ  from  similar  changes  that 
might  be  initiated  in  altogether  lifeless  substance.  But  when 
a  nasturtium  vine  places  its  leaves  perpendicular  to  the  rays 
of  the  sun,  accomplishing  this  by  a  very  complicated  series 
of  changes  in  the  shapes  of  cells  and  in  the  living  substance 
itself  of  the  leaf-stems,  there  is  a  reaction  out  of  proportion  to 
the  immediate  ca.use  and  possible  only  since  a  mechanism  exists, 
and  this  mechanism  has  been  put  in  motion  by  the  sunlight. 
Irritable  responses,  as  made  by  the  plants  and  animals  of  to-day, 
indicate  not  only  mechanism  capable  of  responding,  but  con- 
note also  an  inheritance  through  the  ages  in  view  of  which 
the  mechanism  is  what  it  is.  As  in  all  other  manifestations  of 

33 


498  Minnesota  Plant  Life. 

the  living  substance,  irritable  phenomena  are  related  with  past 
time  as  well  as  with  the  present.  Here,  indeed,  lies  one  of  the 
principal  differences  between  a  living  thing  and  an  insentient 
mechanism  composed  of  springs,  wheels,  pulleys,  levers  and 
rods.  One  has  a  past ;  the  other  is  a  creature  of  the  present. 

Irritable  behavior  of  living  substance.  While  all  manifes- 
tations of  irritability  must  be  attributed  to  responses  by  the 
living  substance,  it  is  convenient  to  examine  first  those  responses 
made  by  living  substance,  as  such;  and  later  to  consider  the  irri- 
table responses  of  cells  and  organs.  A  further  distinction  may  be 
made,  for  purposes  of  analysis,  between  induced  and  automatic 
responses.  Really,  all  responses  are  induced  by  stimuli ;  but 
if  these  stimuli  originate  within  the  living  substance — as  a  result 
of  subtle  rearrangements  of  its  component  structure — the  re- 
sponses may  then  be  termed  automatic,  in  contradistinction  to 
responses  which  are  plainly  induced  by  external  stimuli.  Thus, 
the  extraordinary  marshalling  into  groups  of  the  component 
parts  of  a  mass  of  living  substance,  before  division  of  a  cell 
takes  place,  would  be  termed  automatic ;  the  lashing  of  a  swim- 
ming thread,  such  as  that  of  a  spermatozoid,  is  also  automatic ; 
but  the  contraction  of  a  portion  of  protoplasm  when  exposed 
to  a  slight  electric  shock  would  be  regarded  not  as  automatic 
but  as  induced. 

Examples  of  automatic  irritable  phenomena  in  living  sub- 
stance are  very  numerous.  Here  should  be  classified  the  stream- 
ing movement,  the  lashing  movement,  the  crawling  movement, 
and  the  spontaneous  contractions  of  protoplasm.  Here,  too, 
should  be  grouped  those  amazing  evolutions  by  which  the 
nucleus  of  a  cell  divides  itself  into  two,  prior  to  cell  division. 
It  is  by  no  means  a  mere  halving  of  the  nucleus  that  then 
takes  place ;  but  a  complex  segregation  of  certain  portions  on 
one  side  and  certain  portions  on  the  other  side  of  a  neutral  line, 
the  whole  recalling  military  marchings  and  countermarchings, 
or  the  working  of  some  ingenious  manufacturing  contrivance, 
such  as  the  pressroom  of  a  metropolitan  newspaper.  Automatic 
movements  are  dependent  upon  suitable  outward  conditions,— 
as  are  also  induced  movements.  Thus,  too  high  or  too  low  a 
temperature,  too  strong  or  too  weak  illumination,  or  some 
other  condition  of  the  environment,  may  prevent  their  appear- 


Minnesota  Plant  Life.  499 

ance.  They  are  not,  however,  the  normal  immediate  responses 
to  the  presence  of  certain  temperature  or  light  conditions  and, 
therefore,  cannot  be  regarded  as  actually  caused  by  light  or  heat, 
as  are  certain  induced  movements. 

Among  induced  responses  of  living  substance  might  be  men- 
tioned the  change  in  position  undergone  by  particles  of  leaf- 
green  when  the  illumination  becomes  intense.  In  many  higher 
plants  the  particles  of  leaf-green,  so  abundantly  distributed 
through  the  cells  of  the  leaves,  are  shaped  like  two  watch- 
crystals  faced  together.  That  is,  they  are  lens-shaped  and 
biconvex.  When  exposed  to  weaker  illumination  they  custom- 
arily turn  their  broad  faces  towards  the  light;  but  if  the  illum- 
ination becomes  too  intense  they  shift  their  positions  until  only 
their  edges  are  presented  to  the  rays.  Another  example  of  an 
induced  irritable  movement  is  afforded  by  some  free-swim- 
ming cells  that  normally  swim  either  towards  a  source  of  light 
or  away  from  it.  Certain  organisms  of  microscopic  size  are 
known  to  swim  invariably  towards  the  positive  or  towards  the 
negative  pole  of  an  electric  field.  Still  others  are  directed  by 
chemical  substances  in  solution.  Thus,  the  minute  Euglena 
plants  swim  towards  concentration  of  organic  substances  that 
would  be  suitable  for  food,  and  spermatozoids,  directed  by 
chemical  emanations,  swim  towards  the  eggs  of  their  species 
So  invariably  are  these  directive  movements  induced  that  if  a 
very  weak  solution  of  sugar,  malic  acid,  or  whatever  the  specific 
chemical  may  be,  is  placed  in  a  capillary  glass  tube  and  then 
immersed  in  a  dish  of  distilled  water  containing  stimulable 
spermatozoids,  they  will  swim  into  the  tube  by  thousands. 
From  such  experiments  it  is  learned  that  the  spermatozoid  finds 
the  egg  with  which  it  is  to  fuse,  because  it  is  induced  to  swim 
from  a  weaker  to  a  stronger  solution  of  some  substance  that  the 
egg  is  excreting. 

Still  another  example  of  an  induced  movement  is  furnished 
by  the  large  jelly  masses  of  living  substance  characteristic  of 
slime-moulds.  These  have  a  habit  of  climbing  up  upon  the 
bodies  of  herbs  or  other  objects  and  spreading  themselves  out 
on  the  leaves  or  elsewhere,  as  a  preliminary  to  the  production 
of  spores.  The  significance  of  such  a  habit  is  not  hard  to  un- 
derstand, for  through  it  the  spores  when  produced  are  likely 


Minnesota  Plant  Life. 
, 

to  obtain  wider  distribution.  The  movement  is,  no  doubt,  in- 
duced by  the  force  of  gravity.  Stimulated  by  this  force  the  jelly 
mass  crawls  upward.  Such  behavior  is  an  excellent  example  of 
an  irritable  response  to  an  outward  stimulus.  Clearly  such  an 
upward  movement  is  distinctly  different  from  the  upward 
movement  of  a  balloon.  The  jelly  mass  is  much  heavier  than 
the  air  and  it  crawls  away  from  the  surface  of  the  earth  because 
the  force  of  gravity  induces  its  mechanism  to  make  this  form 
of  response.  There  is  a  great  difference  between  mechanism, 
as  such,  and  the  material  of  which  the  mechanism  is  constructed. 
If  it  were  not  alive  it  would  respond  to  the  force  of  gravity  pre- 
cisely as  a  stone  does. 

Irritable  behavior  of  plant  organs.  While,  as  has  been 
stated,  all  phenomena  of  irritability  must  receive  their  ultimate 
explanation  in  the  structure  and  nature  of  the  living  substance, 
yet  it  is  expedient  to  separate,  in  an  analysis,  the  irritable  be- 
havior of  organs  from  that  of  living  substance.  As  before,  and 
under  the  same  conditions,  the  manifestations  may  be  grouped 
either  as  automatic  or  as  induced. 

Among  examples  of  automatic  irritable  phenomena  in  a  grow- 
ing organ,  there  might  be  named  the  movements  of  growth, 
as  they  are  termed.  'It  may  be  discovered  by  careful  observa- 
tion that  a  stem  in  process  of  elongation  does  not  increase  in 
length  regularly,  but  in  such  a  way  that  the  tip  describes  a  spiral 
in  the  air.  This  growth-movement  is  termed  nutation.  It 
may  best  be  detected  by  taking,  at  intervals  of  a  few  moments, 
a  continuous  series  of  photographs  of  some  growing  shoot. 
By  comparison  of  the  different  pictures  it  will  be  learned  that 
the  stem  has  not  been  thrust  straight  up,  but  that  it  has  been 
nodding,  first  to  one  side  and  then  to  the  other,  in  a  highly 
erratic  manner.  In  part,  the  movement  is  determined  by  ex- 
ternal conditions  of  nutriment,  illumination,  temperature,  among 
others,  but  there  is  also  an  automatic  quality  in  the  movement 
of  nutation  which  permits  it  to  be  mentioned  here. 

Another  remarkable  automatic  movement — in  this  instance, 
in  a  mature  organ — is  that  of  the  leaflets  in  an  exotic  member 
of  the  pea  family,  known  as  the  "telegraph  plant."  The  leaf  of 
this  plant  is  composed  of  a  large  central  and  two  lateral  and 
smaller  leaflets.  The  central  leaflet  is  quiet,  but  the  two  small 


Minnesota  Plant  Life.  501 

blades  keep  up  a  flapping  motion,  which,  although  slow,  is 
plainly  visible.  Of  what  use  this  may  be,  no  one  clearly  knows. 
Possibly  it  serves  to  frighten  away  leaf-cutting  ants,  but  this 
seems  doubtful.  In  any  event  such  a  movement  is  typically 
automatic.  It  takes  place  only  under  suitable  conditions  of 
temperature  and  nutrition,  but  these  conditions  cannot  be 
termed  the  cause  of  the  movement.  That,  indeed,  must  be 
very  complex  and  should  be  sought  in  the  intimate  structure 
of  the  plant. 

Induced  movements  of  organs  are  numerous — so  numerous, 
indeed,  that  it  may  be  said  of  every  organ  that  it  is  capable 
of  making  a  variety  of  irritable  responses  to  the  impulses  reach- 
ing it  from  the  outer  world.  Among  the  various  effective 
stimuli  are  the  forces  of  gravity,  light,  heat,  magnetism  and 
electricity,  also  air,  moisture,  matter  in  solution,  matter  in 
contact,  and  various  mechanical  tensions,  pressures  and  strains. 

While  not  the  only  methods  of  response,  very  characteristic 
reactions  of  organs  to  an  outward  stimulus  are  by  maintenance 
of  positions  parallel  with,  or  perpendicular  to,  the  force-lines 
of  the  stimulus,  or  by  curvature  in  some  definite  direction. 
Thus,  under  the  constant  action  of  the  force  of  gravity,  shoots 
ordinarily  maintain  an  erect  position,  growing  against  the  force ; 
while  roots  grow  with  the  force.  Both  positions  are  manifesta- 
tions of  irritability.  In  the  various  plant-positions,  there  is 
also  to  be  distinguished  an  automatic  type  of  irritability.  Thus, 
quite  apart  from  the  force  of  gravity,  root  and  shoot  grow  in 
opposite  directions.  They  will  do  this  if  whirled  on  a  hori- 
zontal wheel,  as  in  the  experiment  of  Knight,  who  thus  demon- 
strated the  similarity  between  the  response  to  centrifugal  force 
and  that  to  gravity,  for  in  such  an  apparatus  shoots  grow 
towards  the  center  and  roots  towards  the  rim.  There  is,  so  to 
speak,  a  polarity  in  plant  organs.  They  have  tips  and  bases,  or 
upper  and  under  sides,  or  fixed  and  free  ends.  In  the  main- 
tenance of  polarity  automatic  influences  are  at  work.  For  this 
reason  counteraction  of  the  force  of  gravity,  by  revolution  of 
the  plant  upon  a  vertical  wheel,  does  not  permit  the  plant  or- 
gans to  become  shapeless  and  unrecognizable.  On  the  con- 
trary, they  retain  their  polarity,  though  their  direction  may 
be  different. 


502  Minnesota  Plant  Life. 

Nevertheless  the  constant  action  of  the  force  of  gravity  may 
be  said  to  induce  the  upright  position  of  a  normal  shoot.  It 
is  true  this  position  may  be  modified  in  a  variety  of  ways 
by  a  variety  of  forces,  or  by  the  so-called  correlations  of  growth. 
A  lateral  ray  of  sunlight  may  force  a  shoot  out  of  the  perpen- 
dicular, either  towards  the  ray,  as  in  the  nasturtium,  or  away 
from  it,  as  in  the  ivy.  And  in  an  organ-complex,  such  as  the 
branching  crown  of  a  tree,  the  mutual  interrelations  of  the  twigs 
cause  positions  to  be  taken  which  are  quite  the  reverse  of  those 
that  they  would  take  if  growing  by  themselves.  The  young 
sapling  of  the  soft  maple,  for  example,  grows  erect.  When  it 
begins  to  branch  the  branches  form  angles  with  the  primitive 
stem,  and,  in  a  mature  tree,  twigs  will  be  found  growing  directly 
downward,  perhaps — a  thing  that  they  would  not  do  unless 
correlated  with  the  other  branches  of  the  tree.  Sometimes  the 
erect  position  of  one  organ  inhibits  such  a  position  in  a  sub- 
ordinated organ.  An  illustration  of  this  is  often  seen  in 
pine  trees.  As  long  as  the  terminal  shoot  is  active  it  is  the  only 
one  to  maintain  the  erect  position ;  but  let  it  be  destroyed  and 
a  1'ateral  shoot  will  bend  into  the  erect  position.  Evidently  the 
lateral  shoot  has  the  structure  fitted  to  maintain  the  erect  posi- 
tion and  was  prevented  from  so  doing  simply  because  correlated, 
as  a  lateral  branch,  with  the  original  terminal  axis. 

When  all  necessary  reservations  have  been  made  it  becomes 
apparent  that  most  plant  organs  are  strongly  influenced  by  the 
direction  from  which  the  forces  of  light  and  gravity  may  strike 
them.  Evidence  of  this  may  be  seen  whenever  a  grass  stem 
beaten  down  by  hail  lifts  itself  again,  or  in  the  leaning  towards 
the  light,  of  plants  in  a  window-garden. 

Besides  the  manifestations  of  irritability  that  have  been 
alluded  to,  there  are  many  others,  to  which  but  a  cursory  refer- 
ence can  be  made.  Roots  bend  from  a  less  moist  to  a  more 
moist  substratum.  They  commonly  bend  away  from  the  light. 
Greater  oiMess  warmth  may  exert  a  directive  influence  upon 
growth.  Chemical  substances  in  solution  influence  aquatic  or- 
gans. A  number  of  organs  grow  towards  oxygen  or  towards 
the  air.  Others  grow  away  from  it.  Thus,  if  several  pollen- 
spores  germinate  in  a  drop  of  sugar  solution  all  the  pollen- 
tubes  will  grow  towards  the  center  of  the  drop,  and  away  from 


Minnesota  Plant  Life.  503 

the  air  in  which  it  may  be  suspended.  Some  organs  place 
themselves  against  a  stream  of  water,  while  others  grow  with 
the  current.  Some  organs  bend  towards  the  positive  electric 
pole,  others  towards  the  negative.  Growth  in  a  magnetic  field 
shows  that  magnetic  force  has  its  directive  influence.  Contact 
induces  curvatures.  Root  tips  upon  touching  a  hard  body  be- 
come convex  toward  the  body  that  touches  their  sensitive 
area.  Tendrils,  on  the  other  hand,  and  twining  stems  be- 
come concave  toward  the  body  that  touches  their  sensitive 
surfaces,  thus  enabling  themselves  to  seize  hold  of  supports. 
A  wound  often  induces  curvature.  Thus,  branding  a  root  tip 
with  a  hot  wire  induces  it  to  curve  to  one  side.  In  general,  the 
plant  is  a  sensitive  creature  feeling  easily  slight  changes  in  the 
surroundings  and  accommodating  itself  to  them,  so  far  as  pos- 
sible, by  irritable  curvatures. 

'Special  organs  of  irritability  are  present  in  many  plants.  Of 
these  the  piilvinns  of  the  pea  family  and  the  tendril  of  gourds 
or  smilax,  might  be  cited  as  illustrations.  At  the  base  of  each 
leaflet  of  a  bean  plant,  for  example,  may  be  noticed  a  short  sec- 
tion of  the  leaf  stem  in  which  the  color  is  deeper  green  than 
elsewhere.  A  similar  section  exists  at  the  base  of  the  main 
leaf-stem.  Such  an  area  is  called  a  pulvinus  and  is  the  motile 
organ  of  the  leaf.  When  provided  with  pulvini,  as  are  beans, 
clovers,  wood-sorrels  and  several  other  plants,  the  leaves  easily 
change  their  positions  under  slight  stimuli.  Clover  leaves  ex- 
amined at  night  will  be  found  to  be  in  sleep-positions  different 
from  those  of  the  day,  and  doubtless  induced  by  falling  tem- 
perature and  less  illumination.  Leaves  with  pulvini  commonly 
make  automatic  movements,  most  noticeable  in  the  telegraph 
plant  mentioned  above.  Some  leaves  with  pulvini  are  highly 
sensitive,  and  of  this  condition  the  well-known  Mimosa  is  an 
example.  In  this  plant  a  slight  shock  or  burn  causes  the 
numerous  leaflets  to  fold  together  and  the  whole  leaf  to  drop 
downward  on  its  stem.  The  rapidity  with  which  the  action 
takes  place  makes  it  very  striking,  but  it  is  not  particularly 
different,  except  in  amplitude  and  celerity,  from  many  other 
sensitive  reactions.  All  plants  are  sensitive  plants,  if  one 
watches  them  closely  enough.  The  curious  Venus's  fly-trap  of 
Carolina  is  another  quickly-moving  variety.  Its  leaf-blade  may 


504  Minnesota  Plant  Life. 

snap  together  along  the  pulvinus-like  midrib,  quite  after  the 
manner  of  a  steel  trap.  The  mere  contact  of  an  insect  is 
enough  to  set  off  the  irritable  mechanism. 

A  tendril  is  a  singularly  ingenious  contrivance.  At  first  it 
is  straight,  or  with  the  free  end  slightly  bent.  It  sweeps  about 
slowly  with  the  growth-movement  known  as  nutation,  and  w7hen 
its  tip  encounters  a  resistant  body,  the  tendril  becomes  bent 
around  the  object  that  it  has  found  and  fastens  itself  to  it. 
Then  the  whole  cylindrical  organ  coils  into  a  spring,  drawing 
the  leaf  or  stem  up  against  the  support.  Later  the  tissues  of 
the  tendril  become  woody,  giving  strength,  while  the  coiled 
structure  gives  elasticity.  Thus  plants  with  these  organs  are 
the  most  perfect  of  climbers  and  support  themselves  lightly  but 
firmly  upon  their  trellises. 

All  the  responses  to  stimulation  that  have  just  been  reviewed 
would  be  classified  as  curvatures.  When  a  gall-forming  insect 
stings  a  plant,  or  when  a  witches'-broom  fungus  obtains  a  foot- 
hold upon  it,  there  is,  rather,  as  a  result  of  the  stimulation,  an 
abnormal  growth  of  tissue.  Galls,  in  particular,  are  often  very 
extraordinary  structures.  The  huge  purple  root-galls  of  the 
wild  rose,  the  spherical  papery  shells  of  the  oak,  the  little  hem- 
ispherical nodules  on  basswoods  leaves,  the  cone-like  grey 
bodies  on  willows  and  the  great  bushy  tangles  on  black  ashes 
are  all  familiar  objects  in  Minnesota.  In  such  galls  special 
anatomical  structures  are  called  into  existence  by  the  virus  in- 
jected with  the  insect's  sting.  Special  gall-types  characterize 
particular  plants,  and  will  not  be  found  elsewhere.  Between 
the  specific  virus  and  the  specific  character  of  the  living  sub- 
stance of  the  plant  a  relation  exists ;  and  upon  this  depends  the 
anatomical  and  physiological  character  of  the  gall. 

Another  type  of  induced  irritability  of  organs  is  seen  in  the 
arrangement  of  skeleton-tissues,  for  the  large  leaf  will  have  more 
strengthening  material  in  the  stem  than  will  the  small  leaf  of 
the  same  species.  Such  strengthening  areas  are  found  to  lie 
very  exactly  in  the  regions  of  pressure  or  of  tension,  and  may 
be  regarded  as  having  come  into  being  by  the  response  of  cells 
to  such  stimuli.  The  cross-section  of  the  familiar  rhubarb 
leaf-stalk  shows  it  to  be  half-cylindrical  in  form.  The  arched 
side  is  towards  the  ground  and  the  calling  into  existence  of 


Minnesota  Plant  Life.  505 

the  arched  form  of  leaf-stalk  depends  upon  the  action  of  pres- 
sure, owing  to  the  weight  of  the  leaf-blade.  All  the  beautifully 
accurate  arrangements  of  strengthening  beams  and  elastic  tissues 
in  stems  and  leaves  may  be  regarded  as  possible  only  through 
irritability  of  the  living  cells,  some  of  which,  under  pressure, 
thickened  their  walls  to  withstand  it ;  while  others,  in  a  region 
of  flexions,  adopted  elasticity  of  structure. 

Summary  statement.  What  has  been  brought  forward  upon 
the  subjects  of  plant  nutrition,  growth  and  irritability,  suf- 
fices merely  to  direct  attention  to  a  few  of  the  paths  along 
which  investigation  has  proved  profitable.  No  attempt  has 
been  made  in  so  limited  a  space  to  present  a  complete  outline 
of  plant-physiology.  In  cursive  manner,  the  existence  of  a 
living  substance  has  been  affirmed  and  it  has  been  intimated 
that  the  physiological  activity  of  the  plant  is  in  fact  the  physi- 
ological activity  of  living  substance.  For  this  reason,  ad- 
vanced research  must  be  with  aid  of  the  microscope  and  all 
the  other  appliances  of  the  modern  laboratory.  The  secret  of 
the  plant  lies  very  deep  and  is  not  to  be  wrested  from  it  by 
superficial  examination  or  analysis. 

Self  defense.  Not  only  must  the  plant  utilize  the  materials 
and  forces  about  it  and  adapt  its  structure  and  behavior  to  the 
environment,  but  it  is  also  often  called  upon  to  defend  itself 
against  unfavorable  conditions.  Two  of  the  common  animal 
types  of  defense  are  but  sparingly  employed  by  plants.  These 
are  active  opposition  and  night.  Not  being  provided  with 
muscles,  the  plant  can  rarely  run  from  threatening  dangers,  nor 
can  it  often  combat  them  by  an  active  display  of  force.  Among 
the  lower  plants  flight  is  of  defensive  value  for  diatoms  and 
other  motile  varieties.  They  swim  away  from  undesirable  local- 
ities and  seek  those  where  they  can  best  maintain  their  exist- 
ence. Motile  cells,  such  as  spermatozoids  and  swimming 
spores,  may  also  protect  themselves  in  this  manner.  Active 
opposition  is  very  rare,  but  is  practiced,  perhaps,  by  such  a  plant 
as  the  Venus's  fly-trap  when  it  snaps  at  the  insect  that  may 
have  approached  it  with  some  notion  of  feeding  upon  its 
tissues. 

Most  plants  maintain  a  passive  defense  against  unfavorable 
or  harmful  influences.  A  great  variety  of  such  defenses  are 


Minnesota  Plant  Life. 

practiced.  Some  are  structural,  while  others  are  physiological. 
The  principal  dangers  to  which  plants  are  exposed  are  these: 
desiccation,  inundation,  fracture  by  wind  or  water,  poisoning 
by  salts,  over-  or  under-illumination,  over-heating,  cold,  and 
attack  by  other  plants  or  by  animals.  The  defensive  adapta- 
tions against  the  various  inanimate  harmful  influences  have 
already  been  discussed  in  Chapter  XL;  but  there  remain  a  few 
words  to  be  said  concerning  defense  against  other  plants  and 
animals.  The  most  universal  method  is  by  producing  distaste- 
ful or  poisonous  substances  in  the  tissues.  Among  such  should 
be. counted  the  acids,  alkaloids,  tannins  and  resins  that  are 
characteristic  of  many  plants.  By  means  of  these  substances, 
dissolved  in  their  juices,  they  make  themselves  objectionable 
to  grazing  animals,  to  insects  and  snails,  and  even  to  parasitic 
fungi.  Sometimes  the  poisonous  materials  are  projected  to  a 
distance,  as  is  true  of  the  poison-ivy  and  poison-dogwood.  In 
such  instances  the  animals  are  dissuaded  even  from  approaching 
the  plant. 

Another  common  method  of  defense,  especially  against 
animals,  is  the  wearing  of  armor.  This  ordinarily  takes  the 
form  of  prickles,  spines,  or  thorns,  though  it  may  rarely  appear 
as  hard  scales  or  plates.  Armor  is  not  limited  to  the  plants 
of  any  particular  region  or  of  any  adaptational  group.  The 
aquatic  water-fern,  Salvinia,  has  its  sharp-pointed  hairs  to  deter 
small  insects  from  feeding  upon  its  fruiting  areas;  the  meso- 
phytic  hawthorns,  roses,  and  brambles  are  bristling  with  prickles 
and  thorns,  while  the  xerophytic  cacti  and  spurges  are  unap- 
proachable in  the  effectiveness  of  their  defense.  Armor  is  par- 
ticularly useful  to  desert  plants,  for  they  are  most  exposed  to 
attack  by  hungry  animals.  Less  ordinarily  in  mind,  when 
plant-armor  is  mentioned,  is  the  skin  on  leaves  and  green  twigs. 
This,  while  not  defensive  against  animals  of  large  size,  is  suffi- 
cient, perhaps,  to  puzzle  some  of  the  smaller  insects,  and  often 
suffices  to  prevent  the  infection-tube  of  a  fungus  from  obtaining 
an  easy  entrance  to  the  soft  inner  tissues  of  the  leaf  or  stem. 

Mimicry  is  a  peculiar  method  of  defense  adopted  by  some 
plants.  Thus,  an  innocuous  plant  by  its  resemblance  to  a 
poisonous  variety  often  escapes  injury.  In  deserts  some  kinds 
of  plants  are  gray  in  color,  irregular  and  massive  in  shape,  and, 


Minnesota  Plant  Life.  507 

in  sliort.  so  much  like  stones  that  they  are  likely  to  be  passed 
over  as  members  of  the  mineral  kingdom.  Such  an  appear- 
ance must  help  them  just  as  its  green  color  helps  the  tree-toad 
by  making  it  inconspicuous.  Another  kind  of  mimicry  has 
been  thought  to  characterize  certain  tropical  herbs  with  mottled 
leaves.  Some  begonias  and  aroids  suggest  themselves  as  ex- 
amples. It  has  been  supposed  that  by  their  resemblance  to 
snakes  they  may  avert  danger  to  themselves,  from  grazing 
animals.  The  sensitive  plant,  which  at  a  slight  shock  drops 
into  an  apparently  shriveled  and  dry  condition,  may  by  this 
behavior  startle  or  deceive  animals  that  would  otherwise  feed 
upon  its  foliage. 

Utilization  of  allies  is  a  not  uncommon  method  of  defense. 
Thus,  plants  growing  in  hedge-rows  obtain  protection  because 
the  thorny  or  impenetrable  vegetation  about  them  is  sufficient 
to  withstand  the  attack  of  animals.  Some  plants  may  obtain 
defense  by  hiding  themselves  in  out  of  the  way  places,  but  this 
is  scarcely  a  calculable  matter.  A  peculiar  alliance  is  that 
which  exists  in  the  tropics  between  certain  trees  and  ants.  In 
these  regions  leaf-cutting  ants  are  abundant  and  some  trees,  by 
the  secretion  of  sweet  liquid  on  the  twigs,  attract  large  num- 
bers of  warrior  ants  that  feed  upon  the  honey.  The  plants  even 
develop  shelter  for  such  ants  and  when  leaf-cutting  ants  attempt 
to  ascend  the  tree  the  honey-eaters  swarm  out  and  offer  battle. 
An  ant-defended  tree,  such  as  a  Cccropia,  is  an  extraordinary 
object.  A  slight  blow  upon  the  trunk  calls  out  thousands  of 
angry  ants  from  every  crevice.  By  keeping  such  a  body-guard 
of  insects,  the  plant  undoubtedly  protects  itself.  Many  other 
such  alliances  might  be  mentioned  but  one  further  example 
must  suffice. 

Seedlings  of  trees  are  particularly  exposed  to  harm.  As  in 
man,  so  in  plants,  the  expectation  of  life  is  at  first  decidedly 
low.  Most  seedlings  perish  before  they  are  firmly  established 
and  those  that  are  fortunate  enough  to  persist  and  finally  to 
mature  into  sapling-trees  have  generally  been  nursed  along  b\ 
surrounding  plants  which  have  happened  to  be  of  kinds  not  un- 
favorable to  the  seedling  itself.  Thus  the  young  red  pine 
plants  make  excellent  nurses  for  the  seedling  of  the  white  pine, 
and  if  the  former  are  abundant  on  the  forest  floor,  the  white 
pines  are  more  likely  to  obtain  a  foothold. 


508  Minnesota  Plant  Life. 

The  maintenance  of  a  plant,  like  that  of  an  animal,  depends, 
in  the  words  of  Herbert  Spencer,  upon  a  continuous  adjustment 
between  internal  and  external  conditions.  If  this  adjustment 
ceases  to  be  made,  death  is  the  result.  Every  fundamental 
problem  of  life  that  confronts  the  animal,  confronts  also  the 
plant.  The  solution  may  be  by  different  processes,  but  solu- 
tion there  must  be  in  the  one  instance  as  in  the  other.  Struc- 
turally and  physiologically  the  living  substance  of  plants  and  of 
animals  shows  many  resemblances,  and  it  is  not  at  all 
erroneous  to  say  that  plants  and  animals  are  but  different  man- 
ifestations of  the  organizing  power  of  living  substance.  In 
plants  the  constructive  processes  preponderate,  in  animals  the 
energy-producing;  but  fundamentally  the  two  kinds  of  creatures 
are  much  more  decidedly  alike  than  different. 


Chapter  XLV. 

Maintenance  of  the  Plant  Species* 


The  methods  by  which  individual  plants  are  maintained  as 
units  in  Nature  may  be  regarded  as  methods,  also,  for  main- 
tenance of  the  species.  A  species  consists  of  all  the  individ- 
uals, living  and  extinct,  that  are  judged  to  form  a  single  and 
definite  line  of  inheritance  and  are  of  practically  identical 
structure.  Thus,  one  speaks  of  the  human  species,  meaning 
not  only  the  men  and  women  of  to-day,  but  also  their  an- 
cestors. In  the  same  manner  one  may  take  into  the  mind 
the  conception  of  a  plant-species,  such  as  the  dandelion,  or 
the  white  pine.  While  the  lives  of  individuals  are  compara- 
tively brief,  the  life  of  a  species  may  be  of  long  duration, 
varying,  perhaps,  from  a  few  hundred  to  many  millions  of 
years.  Most  species  are  more  than  ten  thousand  years  old  —  at 
least  this  is  the  belief  that  has  been  strengthened  by  researches 
in  geology  and  in  the  history  of  development. 

In  order  to  continue  the  chain  of  individuals  that  constitutes 
a  species,  the  living  substance  both  among  plants  and  animals 
has  the  universal  habit  of  separating  portions,  usually  single 
cells,  from  the  mature  body,  and  these,  if  properly  situated, 
will  build  up  new  bodies  from  the  organic  or  inorganic  world 
by  which  they  are  surrounded.  Such  a  process  is  termed  re- 
production. It  is  analogous  to  growth  and  may  be  regarded  as 
a  function  of  living  substance  that  has  become  specialized 
owing  to  the  establishment,  for  each  kind  of  living  thing,  of  a 
life-period.  The  normal  life-period  may  vary  in  different  or- 
ganisms from  a  few  clays  to  many  hundreds  of  years.  Some 
individuals  are  comparatively  ephemeral,  while  others  are  able 
to  maintain  themselves  over  periods  almost  as  long  as  that  of 
human  history.  Whatever  is  the  duration  of  the  life-period,  it 
may  always  be  considered  as  expressing  a  ratio  between  the 
bodily  vigor  of  the  organism  and  the  average  sum  total  of 


5  jo  Minnesota  Plant  Life. 

unfavorable  chances  against  it,  in  the  outer  world.  Thus,  for 
each  kind  of  living  thing  an  hereditary  rhythm  comes  to  be 
established. 

At  first  the  number  of  individuals  in  a  species  may  be  few; 
later,  a  climax  may  be  reached  in  the  maintenance  of  the  spe- 
cies, and  following  this  the  number  of  individuals  may  dwindle 
until  finally  the  species  becomes  altogether  extinct.  There  is, 
therefore,  a  "life  of  the  species"  distinct  from  the  life  of  the 
individual.  For  a  species  to  maintain  itself  through  the  cen- 
turies it  must  be  strong — that  is,  composed  of  strong  individ- 
uals, each  able  to  hold  its  own  in  the  battle  with  other  types  of 
life  and  with  the  forces  of  Nature.  For  this  reason  the  "in- 
stinct of  self-preservation"  characterizes  every  living  thing.  A 
species  composed  of  negligent,  apathetic  or  suicidal  individuals 
could  not  continue  in  competition  with  others  in  which  the 
opposite  qualities  were  developed.  Nevertheless,  although  the 
instinct  to  live  is  universal  among  living  things,  the  necessity 
of  death  is  equally  universal  and  here  one  faces  an  extraordi- 
nary dilemma.  For  the  interests  of  the  species,  each  individual 
is  placed  in  a  contradictory  position.  Yet  the  apparently 
irreconcilable  situation  is  understood  when  it  is  observed  that 
while  the  passion  for  life,  in  an  animal,  serves  to  keep  the 
species  strong,  the  death,  also,  of  the  animal,  at  the  end  of  a 
definite  life-period,  serves  precisely  the  same  end ;  since  in  this 
manner  the  species  may  consist  always  of  fresh,  young  and 
vigorous  organisms  rather  than  in  large  part  of  those  old, 
decrepit  or  shattered.  While  in  the  sphere  of  the  individual 
there  is  no  solution  of  the  problem  of  life  and  death,  it  is 
illuminated  in  the  sphere  of  the  species.  Thus,  death  at  the 
end  of  an  appointed  life-period  has  been  described  by  Weis- 
mann  as  an  "acquired  physiological  trait,"  developed  for  the 
advantage  of  the  species  as  a  whole  and  no  less  useful  than  the 
instinct  to  live  which  characterizes  each  individual. 

With  these  conceptions  in  mind  it  may  be  understood  how 
a  plant  or  animal  species  may  be  regarded  as  a  continuous, 
very  long-lived  organism  in  which,  in  a  rhythmical  succession, 
individuals  constantly  form  and  disintegrate.  Possibly  the  liv- 
ing substance  of  the  species  as  a  whole  might  be  conceived  of 
as  a  sea  in  which  that  of  the  individual  oro-anisms  was  as  the 


Minnesota  Plant  Life.  511 

waves  rising1  and  falling  through  the  whole  period  in  which  the 
sea  existed.  Even  an  ocean,  however,  as  taught  by  geological 
science,  may  disappear;  and  in  the  same  manner  many  species, 
after  existing  perhaps  for  thousands  of  years,  have  become 
extinct.  Schopenhauer  beautifully  illustrates  this  thought  by 
his  figure  of  the  waterfall,  in  which  he  compares  the  lions  of  the 
desert  to  the  drops  of  water  that  hurry  to  the  brink  of  a 
cataract,  are  poised  there  for  a  moment,  and  then  plunge  into 
the  abyss  below.  The  lion  species  continues,  like  the  fall,  and 
the  lion  quality  persists — just  as  the  rainbow  crowns  the  spray 
so  long  as  water  flows  and  rocks  are  strong. 

Reproduction  in  its  broad  sense  may,  therefore,  be  defined 
as  that  form  of  growth  in  which  a  species  bridges  the  gap  from 
individual  to  individual.  It  is  not  a  process  by  which  new 
organisms  are  created,  but  one  by  which  the  immortal  and  un- 
derlying living  substance  may  keep  intact  the  chain  of  individ- 
ual bodies  that  constitutes  the  species. 

Propagation.  It  is  customary  to  classify  reproductive  phe- 
nomena as  propagative  and  as  reproductive  in  the  narrower  sense. 
Propagation  is  a  term  applied  to  all  processes  by  which  new 
individuals  come  into  existence  through  divisions  of  the  parent 
body  other  than  in  the  formation  of  special  reproductive  cells. 
Thus  the  growth  of  new  potato  plants  from  the  bud's  or  "eyes" 
on  the  tubers,  the  multiplication  of  house-plants  or  trees  by  cut- 
tings, buds  or  grafts,  the  development  of  blackberries  from 
bent-over  canes,  of  strawberries  from  runners,  of  onions  from 
aerial  bulbs,  are  all  classified  as  forms  of  propagation.  Such 
processes  are  indicative  of  strong  regenerative  powrer  in  plants, 
but  it  should  be  noticed  that  considerable  difference  exists 
among  different  plants  in  their  ability  to  propagate.  Some, 
like  the  willows,  propagate  very  easily,  others,  like  the  castor- 
oil  plant,  with  difficulty.  Propagative  or  regenerative  power 
may  exist  in  most  of  the  vegetative  organs,  and  sometimes  in 
true  reproductive  areas  like  spore-cases,  spermaries  or  egg- 
organs,  (ienerally  speaking,  however,  propagation  is  a  func- 
tion of  the  vegetative  tract  and  is  most  common  in  the  least 
specialized  portions.  Roots  and  stems,  for  example,  much 
more  frequently  give  rise  to  new  individuals  than  do  leaves, 
flower-stalks,  petals  or  seed-coats.  In  some  groups  of  plants, 


§12  Minnesota  Plant  Life. 

* 

such  as  the  mosses,  propagation  is  abundant;  in  others,  such 
as  the  mustards,  it  is  rare  or  unusual.  Special  propagative 
bodies,  like  the  gemmae  of  the  umbrella-liverwort,  the  bulbils 
of  ferns  or  of  tiger-lilies,  and  the  brood-cells  of  many  mosses  and 
fungi  are  not  uncommon.  When  they  are  one-celled  they  are 
difficult  to  distinguish  from  true  spores. 

Of  important  propagative  organs  among  higher  plants  should 
be  mentioned  the  rootstocks,  tubers,  bulbs,  corms  and  trailing 
stems  of  many  varieties  of  herbs.  Here,  too,  should  be  in- 
cluded certain  buds,  such  as  the  separable  buds  of  pondweeds 
and  bladderworts ;  and  the  offsets,  stolons,  suckers,  runners, 
and  other  branches  with  propagative  tendencies.  The  leaf  of 
the  walking-fern,  and  the  leaves  of  some  begonias  have  strong 
propagative  power.  In  mosses  almost  any  portion  of  the  body, 
if  isolated,  proceeds  to  develop  a  new  individual. 

Reproduction.  Reproduction  in  the  narrower  sense,  as  it 
takes  place  in  organisms  that  have  developed  the  cell  habit, 
begins  by  the  formation  upon  the  parent  body  of  special  re- 
productive cells.  These  are  either  perfect  or  imperfect.  Per- 
fect reproductive  cells  are  those  that,  after  separation  from  the 
parent  body  will,  if  conditions  are  favorable,  develop  into  new 
organisms.  Such  cells  are  called  spores.  Imperfect  reproduc- 
tive cells  are  those  that  will  not  normally  at  once  develop  into 
new  organisms,  but  will  fuse  together  in  pairs  as  a  preliminary 
to  development.  Such  fusing  cells  are  called  gametes,  and  ordi- 
narily a  division  of  labor  exists  among  gametes  in  view  of  which 
some,  in  a  species,  are  motile,  or  at  least  mobile,  and  active, 
while  the  others  are  quiescent  or  passive.  The  motile  gamete 
is  called  a  spermatosoid  and  the  quiet  gamete  is  called  an  egg. 
In  certain  lower  algae,  such  as  the  water  silk,  both  gametes  are 
provided  with  swimming  lashes  and  are  consequently  motile. 
In  higher  types,  however,  one  gamete  retained  the  motile  char- 
acter while  the  other  lost  it  and  as  a  consequence  of  its  quiet 
life,  grew  larger.  Thus  arose  the  distinction  between  male 
and  female  cells,  a  distinction  that  lies  almost  as  deep  as  that 
between  plant  and  animal  cells.  In  both  kingdoms  similar 
conditions  have  arisen,  and  in  both,  the  formation  of  eggs  and 
sperms  is  a  normal  and  constant  character  in  all  species  above 
the  very  lowest  in  the  scale.  In  both  kingdoms  the  sperms 


Minnesota  Plant  Life.  513 

are  generally  provided  with  swimming  lashes,  or  their  vestiges, 
though,  sometimes,  as  in  red  algae,  these  are  altogether  lost 
and  the  sperms  depend  upon  water  currents  for  their  transfer 
to  the  eggs. 

After  a  sperm  and  egg  have  fused — by  a  complex  process 
entailing  a  profound  rearrangement  and  combination  of  parts — 
the  resultant  cell,  known  as  the  fecundated  egg,  becomes  capable 
of  elaborating  a  new  organism. 

There  are,  then,  in  the  plant  world,  four  types  of  repro- 
ductive cells:  i,  the  originally  perfect  cell  or  spore;  2,  the  im- 
perfect motile,  male  cell  or  sperm ;  3,  the  imperfect  quiet,  female 
cell  or  egg,  and  4,  the  secondarily  perfect  cell  or  fecundated  egg. 
The  story  of  plant  reproduction  concerns  the  formation,  struc- 
ture and  behavior  of  each  of  these  four  types  of  cell  and  the 
interrelations  that  arise  between  them,  their  products  and  the 
mature  areas  of  the  individual  upon  which  they  are  produced. 

Production  of  spores.  Almost  all  spores  are  of  microscopic 
size.  In  quantity,  they  appear  as  a  dust.  The  spores  of  a 
puff-ball  or  the  pollen  of  an  Easter  lily  will  illustrate  this. 
There  are  two  principal  methods  of  spore  production.  They 
may  be  formed  either  from  superficial  cells  of  the  body,  by 
abstriction,  or  from  the  contents  of  special  cells  known  as  spore- 
mother-cells.  The  former  method  is  illustrated  by  the  blue 
moulds,  mushrooms,  red  algae  and  related  plants,  in  which  cer- 
tain superficial  cells  pinch  off  their  free  ends  as  one  or  more 
special  spore-cells.  The  latter  method  is  much  more  universal, 
and  characterizes  mosses,  ferns  and  all  higher  plants.  Further- 
more, it  is  the  method  common  in  many  types  of  algae,  such 
as  the  brown  seaweeds,  and  in  many  fungi,  such  as  the  black 
moulds,  fish-moulds,  and  sac-fungi.  Spore-mother-cells  may 
produce,  in  different  types,  from  one  to  many  hundreds  of 
spores.  Large  numbers  arise  in  the  mother-cells  of  the  giant 
kelp,  the  fish-moulds  and  the  black  moulds.  In  many  sac- 
fungi  the  number  is  commonly  two,  four  or  eight,  while  in  liver- 
worts, mosses,  ferns  and  the  higher  plants  four  spores  are  ordi- 
narily produced  from  each  mother-cell,  except  in  the  instance 
of  embryo-sacs. 

Spore-producing  areas  are  often  aggregated  as  definite  or- 
gans. Examples  of  such  are  the  gills  of  mushrooms,  upon 

34 


Minnesota  Plant  Life. 

which  the  spores  form  a  superficial  layer,  and  the  various  cap- 
sules containing  numerous  mother-cells — such  as  those  of 
mosses  and  ferns,  or  the  pollen-sacs  of  flowering  plants.  An- 
other aggregate  body  is  seen  in  the  fruit  of  the  cup-fungus, 
where  the  lining  consists  of  numerous  sacs  in  each  of  which  a 
definite  number  of  spores  is  formed. 

In  any  case,  spores  arise  by  the  division  of  preexisting  cells 
of  the  body  and,  after  formation,  they  are  either  distributed 
to  a  distance  or  retained  upon  the  body  and  permitted  to  ger- 
minate near  the  point  where  they  arose.  The  first  is  the  primi- 
tive and  ordinary  treatment  of  spores,  but  certain  special  types, 
such  as  the  large-spores  (embryo-sacs)  of  seed-producing  plants, 
are  retained  in  the  rudimentary  seeds  where  they  were  formed 
and  go  through  their  germination  processes  without  distribu- 
tion to  a  distance.  While  maturing,  spores  are  protected, 
moistened  and  nourished  by  various  devices. 

Distribution  of  spores.  If  spores  are  to  be  removed  from 
the  body  of  the  plant  producing  them,  some  method  of  sepa- 
rating them  from  their  point  of  origin  must  be  devised,  and 
some  agency  must  be  found  that  will  transport  them  to  a  spot 
where  they  may  be  able  to  germinate.  Of  abstricted  spores, 
such  as  those  of  mushrooms,  the  separation  is  little  different,  in 
most  instances,  from  a  mere  falling  off  the  support.  Yet  in 
certain  cluster-cup  fungi  special  wedges  of  cell-wall-substance 
are  produced  between  the  successive  spores  of  a  chain  and  by 
means  of  these  they  are  loosened  from  each  other.  And  in  the 
fly-cholera  fungus  the  terminal  spore  is  projected  from  its  stalk 
by  an  explosive  mechanism  that  not  only  separates  the  spore 
from  the  body  of  its  parent,  but  throws  it  some  little  distance 
from  its  point  of  origin. 

In  order  that  spores  formed  internally,  within  spore-mother- 
cells,  may  be  distributed,  the  walls  of  the  spore-mother-cells 
must  be  broken  or  dissolved.  Sometimes  only  the  ends  of  the 
sacs  break  down  to  release  the  spores,  as  in  cup-fungi  and  disc- 
fungi,  and  in  such  the  release  is  sometimes  of  an  explosive 
character.  Again  the  whole  wall  of  the  spore-motlier-cell  may 
dissolve.  This  is  true  of  mosses  and  ferns,  of  club-mosses  and 
higher  plants.  In  these  instances  the  spores  come  to  lie  freely, 
in  the  form  of  a  dry  powder,  within  the  capsules  where  the 
spore-mother-cells  were  developed. 


Minnesota  Plant  Life.  515 

Having  been  liberated  either  from  the  stalk  to  which  they 
were  attached  or  from  the  chamber  in  which  they  were  confined, 
spores  become  units  for  which  various  distributional  devices 
have  arisen.  They  are  borne  away  by  gusts  of  wind,  by  cur- 
rents of  water,  or  by  insects  or  birds  that  have  picked  them 
up  either  by  accident  or  design.  Sometimes  special  assistance 
is  given  them  by  the  parent  plant — directly,  as  when  a  liver- 
wort produces,  in  its  capsule,  writhing  cells  or  clatcrs,  by  the 
struggling  movements  of  which  the  spores  are  scattered ;  in- 
directly, as  when  the  flowering  plant  secretes  honey  near  where 
its  pollen  spores  are  formed,  thus  attracting  insects  that  may 
act  as  carriers.  A  great  many  structures  in  the  plant  world 
have  arisen  to  assist  in  the  distribution  of  spores.  Among 
these  may  be  mentioned  the  erect  stems  of  moss  capsules,  serv- 
ing to  lift  the  spores  into  the  wind,  the  teeth  at  the  margin  of  a 
moss  capsule,  serving  to  sift  out  the  spores  at  favorable  times, 
the  spring-back  of  the  catapult-like  spore-case  of  true  ferns,  and 
the  explosive  pollen-sacs  of  some  flowering  plants;  but  no 
adequate  idea  of  the  variety  that  exists  can  be  given  in  a  limited 
space. 

Sometimes  spores  attend  to  their  own  distribution  by  the 
development  of  motile  organs,  such  as  swimming  threads,  as 
in  fish-moulds  or  green  felts,  or  by  the  production  of  gas  bags 
by  which  they  float  more  easily  in  the  wind — a  condition  that 
exists  among  the  spores  of  the  pines.  Many  pollen-spores  have 
viscid  or  spinous  surfaces  that  facilitate  their  attachment  to 
the  bodies  of  insects,  and  in  general,  the  surface  of  the  spore 
is  commonly  adapted  to  aid  in  distribution. 

Not  infrequently  spores  are  distributed  en  masse  rather  than 
separately.  Orchids  and  milkweeds  furnish  good  illustrations 
of  this  when  several  hundred  of  their  spores  cohere  in  little 
club-shaped  or  saddlebag-shaped  clusters  and  these  are  carried 
away  as  units  upon  the  bills  or  legs  of  insects.  Similar  aggre- 
gates of  spores  are  produced  in  many  lower  plants,  as  in  the 
water-ferns,  Azolla  and  Salvinia;  and  a  somewhat  related  con- 
dition characterizes  the  green  felts.  In  the  latter  each  motile 
perfect  reproductive  body  is  covered  with  swimming  lashes, 
indicating  that  it  is  equivalent  to  an  undivided  group  of  spores, 
each  one  of  which,  if  separate,  would  have  had  its  own  pair 
of  lashes. 


516  Minnesota  Plant  Life. 

It  makes  a  difference,  in  the  economy  of  the  plant,  whither 
the  spores  are  carried,  in  the  distribution.  The  chances  against 
their  finding  spots  favorable  for  germination  are  met  either  by 
their  production  in  enormous  numbers,  or  by  highly  accurate 
methods  of  distribution.  Pines  illustrate  the  former  condition, 
while  orchids,  in  the  management  of  their  pollen  spores,  illus- 
trate the  latter.  Much  depends  upon  the  needs  of  the  sporeling 
— the  plantlet  that  arises  from  the  spore,  upon  its  germination— 
and  many  structures  and  habits  of  spores  are  determined  by  the 
special  requirements  of  the  new  plant.  Thus,  it  happens  among 
scouring-rushes  that  certain  spores  will  produce  little  male 
plants,  while  others  will  produce  small  females.  It  is  important 
that  these  plants  should  not  arise  isolated  from  each  other,  for 
then  it  would  be  difficult  for  them  to  breed.  Therefore,  scour- 
ing-rush  spores  are  provided  with  curious  grappling  append- 
ages by  which  they  cling  together  in  groups.  Again,  in  some 
ferns,  many  club-mosses  and  all  flowering  plants  two  kinds  of 
spores  are  formed,  differing  in  size.  The  large  ones,  contain- 
ing more  food  material,  are  better  suited  to  give  birth  to  female 
plants  of  the  species,  while  the  small  ones,  not  so  well  nourished, 
can  produce  only  males.  Females  need  generally  to  be  larger 
than  males,  for  they  have  to  form  and  nourish  the  larger  gamete- 
cells,  the  eggs.  Such  a  difference  in  size  of  spores  occasions 
difference  in  their  distribution  and  since  it  is  more  economical 
to  transport  the  smaller  bodies  it  happens  that  in  higher  plants 
the  large  spores  are  not  distributed  at  all,  and  the  small  ones 
are  brought  near  them  so  that  upon  germination  of  both,  the 
male  and  female  plants  will  not  be  too  far  apart.  Various  de-- 
vices are  employed  in  the  different  families.  Very  remarkable 
is  the' behavior  of  the  little  water-fern,  Azolla,  in  which  a  cluster 
of  small  spores,  embedded  in  mucilage  and  furnished  with 
barbed  grappling  appendages  upon  the  group,  is  ejected  from 
the  spore-case  and  is  carried  by  water  currents  to  find  an 
anchorage  among  slender,  thread-like  appendages  of  the  large 
spore,  provided  for  that  purpose.  Under  such  an  adaptation 
the  two  sexes  arise  in  close  proximity. 

In  flowers  all  the  extraordinary  arrangements  for  distribu- 
tion of  pollen  are  associated  with  the  peculiar  habits  of  the  males 
and  females  of  the  higher  plants.  The  female  originates,  as  a 


Minnesota  Plant  Life.  517 

microscopic  body,  from  the  undistributed  large-spore  within 
the  rudimentary  seed.  The  male,  therefore,  has  come  to  be 
a  degenerate,  cobweb-like  organism  that  lives  parasitically  on 
tissues  near  the  spot  where  the  female  is  situated.  Thus  pollen 
spores  must  be  distributed  not  haphazard,  as  may  be  the  spores 
of  liverworts,  mosses  and  ferns,  but  to  some  particular  spot — 
either  to  the  end  of  the  rudimentary  seed,  as  in  lower  seed 
plants  such  as  pines,  or,  as  in  higher  seed  plants,  to  a  special 
area  known  as  the  stigma.  Since,  further,  all  enlargements  of 
experience  are  generally  valuable  for  a  plant  as  for  an  animal 
species,  it  happens  that  very  often  pollen  spores  are  carried  from 
one  flower  to  stigmas  of  another,  perhaps  on  another  plant. 
This  is  called  cross-pollination — a  very  different  matter  from 
cross-fecundation  with  which  it  must  not  be  confused.  For 
generations  a  false  analogy  has  existed  in  the  minds  of  almost 
every  one,  botanists  included,  that  there  is  some  comparison  be- 
tween pollination  and  a  breeding  act.  There  is  no  comparison ; 
the  two  processes  are  absolutely  distinct.  Pollination  is  merely 
a  special  type  of  spore  distribution  of  which  the  "puff  of  smoke" 
from  a  puff-ball  is  a  more  general  type.  Fecundation, — the 
blending  of  sperm  and  egg, — is  an  entirely  different  matter. 
In  flowering  plant  species,  after  pollination  has  occurred  and 
small  spores  have  been  placed  in  a  position  where  they  can 
germinate,  male  plants  come  into  existence  and  the  breeding- 
act  takes  place  between  microscopic  organisms  living  parasit- 
ically upon  the  tissues  of  the  spore-producing  individual  of  their 
species.  To  speak  of  the  "sexes"  of  flowers,  or  to  call  stamens 
"male"  structures,  or  to  name  one  cottonwood  tree  a  male 
and  the  other  a  female,  is  in  every  instance  an  indication  of 
ignorance  or  sloth,  or  it  is  a  concession  to  the  ignorance  assumed 
to  exist  among  one's  hearers. 

The  colors,  forms,  structures,  perfumes,  secretions,  positions, 
divisions  of  labor,  and  succession  of  flowers  are  all  intimately 
connected  with  pollen-distributing  devices.  To  discuss  them 
in  detail  would  require  not  merely  volumes  but  libraries.  It 
must  suffice  here  to  remark  that  every  special  type  of  flower 
has  its  own  particular  mechanism  for  spore  distribution.  It 
may  utilize  currents  of  air  or  water,  or  more  commonly  insects. 
Thus,  by  their  interrelations,  the  two  groups  of  living  things, 


518  Minnesota  Plant  Life. 

flowering  plants  and  insects,  have  come  to  be  highly  developed 
as  a  partnership,  constituting,  indeed,  the  most  remarkable 
association  of  all  those  existing  between  plants  and  animals. 

Germination  of  spores.  When  a  spore  enters  upon  the  course 
of  development  through  which  a  new  plant  comes  into  exist- 
ence, it  is  said  to  germinate.  Perhaps  not  quite  all  the  cell 
divisions  that  are  undergone  by  spores  should  be  classed  as 
germination-stages.  In  lichen-fungi,  for  instance,  and  in  many 
others,  spore-cells  before  they  are  separated  from  the  parent 
plant  divide  once  or  more,  even  building  considerable  aggre- 
gates; but  this  behavior  seems  rather  a  multiplication  of  the 
spore-cells  than  true  germination.  Yet  even  among  distrib- 
uted spores  germination  sometimes  begins  before  the  spore 
leaves  the  body  of  its  parent.  This  is  true  of  the  cone-headed 
liverwort,  the  spores  of  which  become .  divided  into  internal 
compartments  before  they  are  scattered  from  their  capsule. 
Such  division  seems  to  constitute  a  true  germination,  for  later 
divisions,  by  which  the  liverwort  first-stage  plant  is  constructed, 
follow  in  unbroken  sequence,  after  the  spore  wall  has  been 
fractured.  Undistributed  spores,  such  as  embryo-sacs,  ger- 
minate at  the  spot  where  they  were  produced. 

If  the  outer  wall  of  the  spore  is  hard  and  brittle,  as  is  usually 
the  case,  it  must  be  broken  by  the  expansion  of  its  contents 
unless  the  sporeling  is  destined  to  remain  principally  or  en- 
tirely within  the  confines  of  the  spore.  The  latter  condition 
actually  obtains  among  many  large-spores  and  is  notably  char- 
acteristic of  the  embryo-sacs  of  flowering  plants.  In  them  the 
female  matures  and  produces  her  eggs  without  ever  leaving 
the  spore  from  which  she  arose.  And  in  smaller  club-mosses, 
quillworts  and  four-leafed  water-ferns  the  male  matures  within 
the  small-spore,  the  wall  of  which  is  finally  broken  open  to 
liberate  the  spermatozoids.  In  all  such  instances  the  sporeling 
nourishes  upon  substances  present  in  the  spore  and  does  no 
independent  vegetative  work.  If,  however,  the  sporeling  is 
destined  to  gather  nutriment  from  the  outer  world  it  very  early 
establishes  itself  as  a  filament,  plate  or  mass  of  cells,  breaking 
or  dissolving  the  original  spore  wall  in  the  process.  Thus,  fern 
spores,  when  ejected  from  their  capsules  upon  a  sufficiently 
moist  surface,  soon  crack  open  and  a  transparent-walled  cell  is 


Minnesota  Plant  Life.  519 

protruded  which  undergoes  rapid  divisions,  growth  and' differ- 
entiation, finally  becoming  a  little  green,  prostrate,  heart- 
shaped  body  with  abundant  root  hairs  and  leaf-green  granules. 
So,  too,  a  fungus  spore  customarily  protrudes,  through  a  cleft 
in  its  wall,  its  first  pale  thread  that  nourishes  upon  whatever 
may  be  its  proper  food,  ultimately  divides,  branches,  grows  and 
brings  into  existence  a  new  fungus  body.  The  pollen  spores 
of  flowering  plants  are  not  infrequently  furnished  with  special 
thin  places  in  their  walls,  through  which  the  tubular  sporeling 
may  easily  emerge.  The  necessary  general  conditions  of  ger- 
mination are  sufficient  warmth  and  moisture  and,  in  some  in- 
stances, the  chemical  stimulus  of  a  proper  food  supply  outside 
the  spore  wall. 

Care  of  sporelings.  In  all  plants  more  or  less  provision  is 
made  for  the  protection  and  nourishment  of  the  sporelings. 
The  spore  commonly  contains  food  material,  or  mechanism  for 
making  it,  and  the  supply  of  food  is  carefully  adjusted  to  the 
needs  of  the  new  plant.  For  this  reason  in  smaller  club- 
mosses,  quillworts  and  water-ferns  the  large  spore  is  furnished 
with  a  comparatively  generous  stock  of  provisions,  in  the  form 
of  starch  and  aleurone  grains,  and  consequently  becomes  as 
large  as  a  grain  of  sand.  Unlike  most  spores,  these  are  dis- 
tinctly visible  without  magnification.  In  the  plants  mentioned, 
the  female,  consisting  of  numerous  cells,  among  which  the  egg 
is  of  prime  importance,  does  little  or  no  independent  vegetative 
work,  and  must  perforce  have  provisions  enough  reserved  for 
her  use  to  enable  her  to  reach  maturity.  Sporelings  with  spe- 
cial necessities,  such  as  pollen-tubes,  have  special  food  sub- 
stances provided  for  them  and  are  stimulated  and  directed  in 
their  growth  by  structural  adaptations  of  the  tissues  around 
them  and  by  chemical  stimuli  that  guide  them  towards  the  eggs 
of  their  species. 

Production  of  spermatozoids.  All  plants  except  the  lowest 
algae  and  fungi  produce  gametes,  or  fusing  cells.  In  a  few 
lower  algae  the  cells  that  fuse  are  alike,  and  in  many  fungi  the 
fusing  cells  become  blended  into  one  body,  in  which  it  is  diffi- 
cult to  distinguish  the  male  and  female  portions.  In  most  of 
the  algae,  in  liverworts,  mosses  and  ferns  and  in  all  the  higher 
plants  there  are  undoubted  distinct  and  dissimilar  sperms  and 
eggs  formed  in  special  cells  or  organs. 


e20  Minnesota  Plant  Life. 

Spermatozoids  are  typically  small  motile  cells  provided  with 
two  or  more  swimming  lashes,  by  means  of  which  they  can 
progress  in  the  water.  The  sperms  of  the  water  silk  and  some 
of  its  relations  are  pear-shaped,  with  the  lashes  on  the  smaller 
end.  Those  of  the  brown  seaweeds  are  somewhat  pointed,  with 
the  lashes  on  one  side.  Those  of  mosses,  ferns  and  higher 
plants  are  commonly  more  or  less  corkscrew-shaped.  In  mosses 
and  club-mosses  two  swimming  lashes  are  formed,  but  in  ferns, 
cycads  and  some  other  higher  plants  that  have  been  studied  the 
number  of  lashes  is  greater.  In  two  high  types  of  plants  the 
lashes  seem  to  have  been  lost,  viz.,  in  red  algae  and  in  most 
flowering  plants.  The  size  of  Spermatozoids  is  almost  inva- 
riably below  the  limit  of  unaided  vision,  but  sperms  of  cycads  are 
plainly  visible,  without  the  assistance  of  a  microscope,  as  tiny 
specks.  As  produced  in  some  of  the  algae,  sperms  contain 
leaf-green  and  considerable  living  substance  in  addition  to  the 
portion  termed  the  nucleus;  but  in  brown  and  red  algae  and 
in  flowering  plants  the  substance  is  principally  nuclear.  Unlike 
many  spores,  Spermatozoids  are  not  formed  as  superficial  cells, 
but  originate  from  the  divisions  internally  of  mother-cells. 
Sometimes,  as  in  the  sphere-alga,  enormous  numbers  arise  from 
a  single  mother-cell,  but  more  commonly  only  one  sperm  de- 
velops in  each.  The  mother-cells  may  be  superficial  and  aggre- 
gated, possibly,  in  exposed  clusters,  as  among  brown  and  red 
algae.  On  the  other  hand  they  may  form  the  core  of  a  solid 
organ,  the  spermary,  as  in  mosses,  liverworts  and  ferns.  In 
the  cone-headed  liverwort,  for  example,  thousands  of  sperm- 
mother-cells  arise  in  each  microscopic  melon-shaped  spermary, 
and,  in  the  course  of  its  life,  a  male  cone-headed  liverwort 
produces  millions  of  such  cells.  In  higher  plants  the  males 
become  greatly  diminished  in  size  and  the  number  of  Sper- 
matozoids that  one  can  produce  during  its  life  is  reduced  to  a 
score  or  less  in  water-ferns,  to  four  in  the  quillwort,  and  to  two 
in  most  seed-producing  plants. 

Distribution  of  Spermatozoids.  Each  spermatozoid  is  care- 
fully constructed  within  its  mother-cell,  and  when  the  latter, 
by  solution  of  its  wall,  opens  to  release  the  tiny  male  cell,  this, 
in  moss  or  fern  types,  swims  rapidly  away.  It  is  carried  in  red 
algae  types  by  water  currents,  and  is  liberated  directly  beside 


Minnesota  Plant  Life.  521 

the  egg  in  seed-plant  types;  for  in  them  the  pollen-tube  con- 
taining the  sperms  grows  into  the  immediate  vicinity  of  the 
eggs  produced  by  the  female  of  the  species.  In  its  movements 
the  spermatozoid  is  guided  by  chemical  stimuli.  The  duration 
of  its  locomotion  varies  in  different  forms,  but  is  rarely  known 
to  exceed  a  few  hours. 

Production  of  eggs.  Plant  eggs  occur  in  all  species  that 
produce  sperms,  for  the  two  kinds  of  cells  are  complementary. 
In  lower  forms  eggs  may  be  motile  and  very  much  like  sperms 
in  appearance.  They  are  distinguished,  however,  by  tiring 
more  quickly  or  by  their  slightly  larger  size.  Typically,  how- 
ever, eggs  have  no  swimming  lashes  and  are  quiet,  passive  cells, 
containing  leaf-green  bodies  or  their  rudiments,  in  such  plants 
as  produce  leaf-green ;  and  they  are  much  larger  than  the  sper- 
matozoids  of  their  species.  Yet  plant  eggs  never  reach  the 
size  of  similar  cells  in  animals,  and  the  largest,  among  which 
should  be  counted  the  eggs  of  pine  trees,  are  little  ovoid,  whitish 
bodies  that  may  be  dissected  out  of  the  rudimentary  seed  where 
the  female  lives  and  produces  them,  and  may  be  picked  up  on 
a  needle  point  for  examination  by  the  unaided  eye.  Most  plant 
eggs  are  microscopic. 

Eggs,  like  sperms,  may  be  produced  in  mother-cells,  some- 
times several  from  each,  but  more  often  only  one.  In  the 
sphere-alga  a  row  of  almost  spherical  eggs  is  produced  in  each 
of  certain  tubular  cells  of  the  filamentous  plant-body.  But  occa- 
sionally eggs  arise  as  the  terminal  cells  of  filaments,  as  in  bass- 
weeds,  where  they  are  protected  by  a  sheathing  layer.  Since 
the  egg  is  a  very  important  cell  in  the  plant  economy,  it  is 
protected  from  harm,  in  all  higher  plants,  by  surrounding  cells ; 
and  thus  in  the  series  of  plants  extending  from  the  liverworts 
to  the  pines,  eggs  arise  in  flask-shaped  organs,  one  egg  at  the 
bottom  of  each  flask.  Clusters  of  such  microscopic  flasks  are 
found  at  the  end  of  the  stem  of  a  female  moss  plant,  on  the 
under  side  of  fern  sexual  plants,  and  embedded  in  the  surface 
of  the  enclosed  female  plant  of  rudimentary  pine  seeds.  The 
egg  organ  serves  the  double  function,  in  such  plants,  of  pro- 
ducing the  egg  and  protecting  the  young  embryo  during  its 
early  stages. 

In  a  few  plants  eggs  are  ejected  from  the  body  of  the  female, 
as  among  many  animals — for  example,  fish;  but  generally  the 


5 2  2  Minnesota  Plant  Life. 

egg  is  not  ejected  and  remains  in  the  organ  where  it  was 
formed,  awaiting  fecundation.  Certain  brown  seaweeds  illus- 
trate the  first  condition.  The  sperms  and  eggs  are  ejected  into 
the  sea  water,  where  they  find  each  other  and  pair.  The  sec- 
ond condition  is  that  of  the  red  seaweeds  and  of  the  whole 
series  from  mosses  to  seed-plants.  Moreover,  it  essentially 
characterizes  the  fungi  and  many  of  the  •  bright-green  algae. 
In  the  management  of  their  eggs  plants  remind  one  somewhat 
of  the  mammals.  Because  of  the  small  size,  and  concealment 
of  plant  eggs  they  are  not  familiar  objects  like  those  of  insects, 
fishes  and  birds. 

On  account  of  their  motile  character,  sperms  are  much  more 
likely  to  be  lost  than  eggs,  consequently  plants  produce  them 
in  much  greater  numbers.  Ordinarily  many  thousand  sperms 
are  constructed  for  one  egg  that  is  fecundated.  But  in 
seed-plants  where  the  male  grows  as  a  parasite  upon  tissues 
close  to  the  location  of  the  female,  only  a  pair  of  spermatozoids 
are  needed,  one  for  each  egg  produced  by  the  female.  In  such 
forms  the  cells  that  are  peculiarly  in  danger  are  the  pollen- 
spores  and  these  are  commonly  formed  in  extraordinary  pro- 
fusion. 

Fecundation.  The  fusing  of  sperm  and  egg  is  known  as 
fecundation.  After  fusion  the  egg  is  said  to  be  fecundated. 
Exactly  the  meaning  of  the  process  is  not  clear.  It  is  known 
that  by  it  the  offspring  derives  the  benefit  of  a  double  line  of 
inheritance,  thus  enabling  it  to  make  favorable  variations,  and 
perhaps  accommodating  it  more  precisely  to  its  surroundings. 
But  a  single  sperm  fuses  with  each  egg,  and  after  this  has  taken 
place  the  egg  commonly  secretes  a  membrane  which  before  was 
absent,  and  thus  shuts  out  later  sperms  that  might  attempt 
a-  fusion.  The  cell  mechanics  of  the  fecundation  process  are 
decidedly  complex,  for  this  is  by  no  means  a  mere  blending  of 
two  masses  of  living  substance,  but  is  an  orderly  reorganization 
of  the  two  structures  into  one.  Not  every  portion  of  the  egg 
is  fitted  to  receive  the  sperm.  There  is  generally  a  particular- 
spot  on  the  egg  surface  at  which  the  fusion  takes  place.  This 
is  known  as  the  "receptive  spot,"  and  in  some  forms  it  differs 
in  color  and  texture  from  the  rest  of  the  egg.  The  swimming 
lashes  of  the  sperm  seem  always  to  blend  with  that  portion  of 


Minnesota  Plant  Life.  523 

the  egg  outside  the  nucleus,  while  the  head  of  the  sperm  fuses 
directly  with  the  nucleus  of  the  egg.  In  cycads  the  swimming 
lashes  of  the  sperm  are  separated  from  its  body  immediately 
after  entering  the  egg  and  may  be  seen  lying  isolated  in  the 
living  substance  around  the  nucleus. 

Behavior  of  the  fecundated  egg.  After  fecundation  has 
been  completed  the  fused  body  is  regarded  as  a  single  cell,  so 
perfectly  have  the  two  components  merged  their  identity  in 
their  common  product.  This  single  cell  is  the  fourth  and  last, 
as  here  classified,  of  the  important  types  of  reproductive  cells 
formed  by  plants.  After  a  period  of  rest  it  normally  segments 
and  grows,  and  by  the  continuation  of  this  process  a  new 
structure  is  brought  into  existence.  This  organism  is  known  at 
first  vmder  the  general  name  of  embryo,  and  matures  into  one  or 
another  type  of  body,  as  may  be  determined  in  the  species  of 
plant  to  which  it  belongs.  Upon  the  whole,  the  behavior  of 
plant  eggs  is  more  various  than  that  of  animal  eggs.  Among 
animals  it  is  customary  for  the  egg  to  mature  into  an  organism 
similar  to  one  of  those  which,  by  the  production  of  sperms  or 
unfecundated  eggs,  cooperated  in  the  formation  of  the  egg 
itself.  This  is  also  true  in  certain  groups  of  plants,  as,  for 
example  among  the  brown  seaweeds,  but  is  by  no  means  the 
general  rule.  In  all  higher  plants,  including  the  red  seaweeds, 
the  higher  fungi  and  the  entire  series  from  liverworts  to  seed- 
plants,  the  egg  does  not  grow  into  an  individual  capable  of 
producing  sperms  or  eggs,  but  invariably  into  a  spore-produc- 
ing organism  or  its  homologue.  There  are,  therefore,  in  the 
plant  world  two  main  types  of  egg  segmentation,  known  re- 
spectively as  the  direct  and  the  indirect.  When  an  egg  seg- 
ments directly  it  forms  an  embryo  that  gradually  matures  into 
a  sexual  plant  or  its  homologue.  When  an  egg  segments  in- 
directly it  forms  an  embryo  that  matures  into  an  asexual  spore- 
producing  organism  or  its  homologue.  From  the  spores  of 
the  asexual  plant  new  sexual  plants  may  arise,  thus  establishing 
the  phenomenon  known  as  "alternation  of  generations." 

The  extraordinary  significance  of  alternation  has  already 
been  discussed  in  Chapter  XIV,  and  need  not  again  be  elu- 
cidated. In  the  simpler  alternating  life  histories  it  would  seem 
that  the  first  few  cells  of  the  young  embryo  become  separated 


Minnesota  Plant  Life. 

from  each  other,  and  each  then  builds  up  a  new  sexual  plant. 
Thus  the  phenomenon  is  equivalent  to  true  twinning  among 
animals.  It  is  extremely  difficult  to  grasp  this  conception 
without  long  familiarity  with  all  the  facts  involved,  but  it  is 
regarded  as  very  certain  that  the  ordinary  plants  of  forest  and 
field  are  really  interpolations  between  the  successive  sexual 
plants  of  their  species.  One  might  say,  indeed,  that  the  real 
fundamental  plants  are,  in  such  species,  only  those  that  form 
sperms  and  eggs,  while  the  great  spore-producing  organisms 
are  "structural  afterthoughts."  In  such  types  as  the  seed- 
plants  or  some  ferns,  the  sexual  plants  are  inconspicuous  and 
even  microscopic.  This  adds  to  the  difficulty  of  comprehend- 
ing the  true  state  of  affairs,  and  it  is  still  further  obscured  by 
the  false  nomenclature  and  wrong  significance  that  has  been 
applied  to  the  parts  of  the  flower.  It  must  be  remembered  that 
in  a  wilted  Easter  lily  there  are  living  numerous  tiny  organisms, 
some  male  and  others  female.  These  are  the  real,  primitive  lily 
plants.  It  is  they  that  have  the  ancestral  line  reaching  back 
into  the  remotest  past.  The  male  plants  are  cobweb-like  tubes 
buried  in  the  tissues  of  the  rudimentary  fruit.  The  female 
plants  are  exceedingly  minute  organisms  hidden  one  at  the 
center  of  each  rudimentary  seed.  The  great  leaf-bearing, 
flower-producing  organism,  rooted  in  the  soil  is  an  "after- 
thought" in  the  species.  When  this  conception  is  taken  into 
the  mind,  then  and  then  only  is  it  possible  to  institute  proper 
structural  comparisons  between  plants  and  animals. 

Very  remarkable  divisions  of  labor  come  to  exist  among 
embryos  in  higher  seed  plants.  In  this  group  each  female 
produces  two  very  minute  eggs,  with  each  of  which  a  sperm 
from  the  pollen-tube  may  fuse.  One  of  the  eggs  forms  an 
embryo  that  can  go  on  and  develop  into  a  plantlet,  and,  as  such, 
constitutes  an  essential  portion  of  every  seed.  The  other  egg 
forms  a  degenerate  embryo,  known  as  the  albumen,  that  fulfills 
its  function  in  the  species  when  it  is  consumed  by  its  stronger 
twin.  This  truly  astonishing  cannibalism  goes  on  in  the  seeds 
of  all  higher  flowering  plants,  but  not  distinctively  in  the  seeds 
of  cycads,  pines  and  their  allies.  In  them  the  so-called  albu- 
men is  the  body  of  the  mother-plant,  and  while  more  than  one 
egg  is  formed  in  pines  the  embryos  that  arise  are  none  of  them 


Minnesota  Plant  Life.  525 

essentially  subordinated.     Each   and   any   may   grow   into   an 
independent  plant. 

When  embryos  are  young  they  often  have  special  nursing 
organs  that  do  not  characterize  their  maturer  stages.  Remark- 
able structures  of  this  sort  are  found  in  the  embryos  of  nastur- 
tiums, orchids,  and  madders,  as  well  as  in  many  others.  They 
may  be  compared  physiologically  with  the  embryonal  organs 
of  birds  and  mammals. 

Care  of  the  young.  The  instinct  of  maternity  so  character- 
istic of  the  higher  animals  is  not  wanting  among  the  higher 
plants.  The  brown  sea-weed,  like  a  fish,  ejects  its  eggs  into 
the  sea,  leaving  them  to  be  fecundated  and  to  develop  and  shift 
for  themselves;  but  higher  plants  have  devised  a  multitude  of 
structures  for  the  care,  protection  and  suitable  establishment  of 
their  progeny.  The  industry  and  pugnacity  of  a  hen  with 
chickens  is  well  known.  Her  duckings,  rufflings  and  scratch- 
ings  are  to  be  interpreted  as  indications  of  her  motherly  instinct 
to  protect  and  nourish  her  young.  Not  otherwise  in  a  plant 
species,  such  as  an  apple,  must  the  greenness  of  the  fruit  be 
interpreted  as  a  device  for  nourishing  the  young  seeds  by  the 
aid  of  sunlight,  the  sourness  as  a  method  of  defending  them 
from  attack,  and  the  subsequent  sweetness,  flavor  and  aroma  as 
adaptations  for  securing  their  distribution  through  the  agency 
of  animals.  While  ripening  its  seeds  the  lady's-slipper  is 
peculiarly  poisonous  to  the  touch.  Many  seeds  contain  deadly 
poisons,  making  them  secure  from  the  attack  of  hungry  animals 
or  birds.  By  thorns,  secretions,  warning  colors,  hard  walls  and 
distributional  contrivances  such  as  burs,  wings,  bristles,  and 
pulp,  seeds  and  fruits  show  the  care  lavished  upon  the  young 
of  the  plant  species.  The  moss  mother,  with  her  green  leaves 
and  root  hairs  collects  and  elaborates  food  for  her  progeny,  the 
capsule.  The  Russian  thistle  covered  with  fruits,  breaks  loose 
from  the  soil  and  rolls  over  the  prairie,  scattering  the  seeds 
along  its  path.  Innumerable  structural  and  physiological 
adaptations  have  in  view  the  one  end  of  assisting  the  young, 
and  in  their  sphere  of  life  plants,  like  animals,  subordinate  the 
needs  of  the  individual  to  the  necessities  of  the  species.  Thus, 
when  germination  has  begun,  female  pine  plants  are  altogether 
consumed  by  the  young  plantlets  in  the  seed.  This  protective 


526  Minnesota  Plant  Life. 

instinct  extends  back  over  more  than  one  generation,. and  not 
only  does  the  mother  plant  assist  the  young,  but  the  spore- 
producing  plant,  from  the  spores  of  which  the  mother-plants 
arose,  helps  the  young,  forming  for  them  seed-coats  and  hold- 
ing the  seeds  upon  the  scales  of  its  cones,  thus  protecting  them 
until  ready  for  distribution  to  a  distance. 

In  the  care  of  the  young,  other  plants  and  even  animals  are 
utilized.  Thus  certain  seedlings  are  nursed  along  by  neighbor- 
ing plants  that  protect  them  from  winds,  drought  or  too 
brilliant  sunshine.  And  animals  carrying  about  upon  their 
feet  or  fur  the  burs  and  sticky  seeds  of  various  species  serve  also 
as  illustrations  of  the  interdependence  between  different  kinds 
of  living  things. 

Words  in  conclusion.  My  labor  is  now  at  an  end,  and  if 
I  have  succeeded  in  portraying  the  vegetation  of  Minnesota  as 
an  assemblage  of  living  creatures,  as  a  world  of  infinite  variety 
yet  with  a  fundamental  unity  of  plan,  as  forms  linked  together 
in  structure,  function,  and  adaptation,  and  as  a  field  worthy  of 
study  and  enthusiasm,  I  shall  feel  content.  Much  has  been  left 
unsaid.  In  the  words  of  Newton,  but  a  few  pebbles  have  been 
collected  on  the  far-stretching  strand  of  truth.  The  whole 
story  will  never  be  told. 


Inde 


Absinthe,  411 

Acacia,  280 

flower,  348 

Acacia,   False,  301 

Acanthus,  367 

Acetic  acid  ferments,  Bacteria 

producing,  114 

Acid,  506 

Prussic,  292 

Aconite,  264 

Aconite  (poison),  273 

Adder's-tongue,  161 

Adoxa,  388, 393 

Age  of  lichens,  96 

Agrimony,  290 

Ailanthus,  305 

Air  chamber,   Bladderwort,  443 

Bulrush,  455 

Duckweed,  443 

Liverwort,  135 

Quillwort,  163 

Sedge,  455 

Air  plant,  472,  481,  489 

pore,  435 

Aitkin  county,  309 

Albumen,  524 

Definition  of.  183 

Alcoholic  fermentation,  73 

Bacteria  of,  102 

Alder,  245,  249,  462 

Bacterial  nodules,  119 

Witches'-broom  on,  74 

Alder,  Black,  249,  312 

Dwarf,  319 

Green,  249 

June-berry,  287 

Tag,  246,  460 

-leafed  buckthorn,  319 

Aleurone  grains,  491 

Alfalfa,  298 

Bacterial  nodules,  118 

Algae,  29,  448,  472,  489,  512,  519 

Deep  water,  453 

Economic   importance   of,  41 


Algae.  Fertilizing  material,  41 

General    remarks,  41 

Groups,  29 

Iodine,  41 

in  leaves  of  floating-fern,  169 

Limestone  formation,  30 

encrusted  with   lime    (Half- 
tone), 31 
in  tank,   Lime-encrusting 

(Half-tone),  35 

Lichens,  93 

Marine,  39,  40 

Noxious,  41 

Number  in  Minnesota,  27 

Nutrition,  48 

Oldest  kinds  of  plants,  42 

Originators  of  all  other  plants,  42 
Origin  of  higher  plants  from,  196 
Parasitic  on  Jack-in-the-Pulpit,  37 
Pig-pen  odor,  41 

Poisonous,  41 

Silica  formation,  31,  41 

Sinter    formation,  31 

Travertine  formation,  31 

Algae,  Blue-green, 

26,  29,  424,  443,  446,  453 
Bright-green,  29,  446,  522 

Brown,  29,  39,  513,  520 

Deep  water,  453 

Flower-pot,  35 

Hot  spring,  31 

Leaf-dwelling,  37 

Lime-secreting,  41 

Red,  29,39,40,446,513,520 

Rolling,  34 

Rock,  467 

Rock-forming,  30 

Silica-secreting,  41 

Skin,  32 

Sphere,  37,  520,  521 

Warm  water,  42 

Algal  fungi,  43 

parasites,  45 

plankton,  443 

Alkali-grass,  226 


528 


Minnesota  Plant  Life. 


Alkaloids,  5o6 

Fungus, 

veratrine,  226 

Alliance  between  trees  and  ants,    507 
Almond,  280, 292 

Alternation  of  generations,      128,  523 
Definition,  123 

Alternate-leafed  cornel,  342 

Alum-root,  283 

American  (Engr.  282),  283 

Rough,  283 

Amaranth,  259,  260,  476 

Amaryllis,  224 

American  alum-root,  283 

elm,  252 

linden,  321 

mountain-ash,  289 

redroot,  319 

senna,  297 

Ammania,  333.  334 

Androsace,  35$ 

Anemone,     264,  268,  269,  426,  475,  479 
Flower  axis,  345 

Resemblance  to  avens,  290 

Resemblance  to  five-finger,       290 
Rue,  269 

Rue,  false  (Half-tone),  270 

Animals,  Diseases,  109 

Fecundated  egg  of  higher,        128 
Habits,  18 

Plants  compared  with,  25 

and  plants,  difference  be- 
tween higher,  128 
Anise,                                                 375 
Annuals,  Desert  plants,                    464 
rings   of   stems,                           197 
Anoka  county,                              327 
Ants  and  trees,  Alliance  between,  507 
Antidotes,  Ivy  and  elder  poison- 
ing,                                                   311 
Antiseptic  surgery,                            114 
Appendaged  waterleaf,                      370 
Apple,                    280,  286,  290,  422,  525 
blossoms  (Half-tone),               288 
Carpels  and  stamens,                 346 
Flower,                                        347 
Fruit,                                            423 
Seed  distribution,  19 
Apple,  Balsam,                                  396 
May,                                             274 
Wild  crab,                                    286 
Apricot,                                        280, 292 
Aquatic  nature  of  terrestrial 
plants,                                              I6 


Aquatic  plants, 

417,  422,  434,  442,  450,  453,  489 

vegetation    (Half-tone),  12 

Arbor-vitae  (see  white  cedar),        186 

moss,  152 

Arbutus,  Trailing,  350,  355 

Architectural  structure  of 

plants,  179,  418,  424,  505 

Arctic  vegetation,  424,  428 

Arctic  dwarfed  raspberry,  291 

Arethusa,  228 

Armor,  Plant,  506 

Arnica,  412 

Aroid,  507 

Arrow-grass,  2oo 

-leafed  violet,  328 

Arrowhead  (Engr.  202.    Half- 
tone,   199,  201),  7,201,450,458 
Floating,  448, 449 
Arrowwood,  388, 390 
Downy-leafed,  391 
Maple-leafed,  391 
Artichoke,                                            410 
Arum,  family,                                     217 
Fruit,                                              217 
Warming-up   color,                     218 
Ash,                        336,  360,  417,  470,  478 
Family,                                            360 
Flower,                                           361 
Black,                                             361 
Black,  Galls,                                504 
Blue,                                              361 
Green,                                           361 
-leaved  maple,                              313 
Mountain,                      280,  286,  290 
Poison,                                           310 
Prickly,                                    305,  307 
Red,                                                361 
Three-leaved.                                307 
White,                                            360 
Asparagus,                           225,  226,  465 
Asphodel,                                           225 
Assimilation,                                       488 
Aster  (Half-tone,  408,  410),  6,  7, 
24,  399,  401,  402,  407, 
415,  427,  469,  470,  472,  478,  479 
dodder,                                           368 
Australian  blue-gum  tree,               434 
Autumn  flowers,                         426,  479 
foliage,                                           426 
Autumn   dandelion,                           403 
Avens,                                                   289 
Resemblance   to  anemone,       290 
Azalia,                                                   350 


Minnesota  Plant  Life. 


529 


Azolla  (see  floating-fern), 

168,443,  515,  516 

Bachelor's-button,  413 
Bacillus,  102 
Bacteria,  29,  101,  424,  446,  459,  492 
Causes  of  disease,  104 
Classification,  101,  102 
clover  root,  117 
Color  producing,  102,  115 
Consumption,  106,  108 
Crop-rotation,  118 
Dairy,  in 
Deep  water,  453 
Disease-producing,  102,  103,  105 
diseases,  109,  453 
Energy  produced  by,  104 
Ferment-producing,  453 
Fertilizers  of  the  soil,  104 
Cheese,  in 
Heat-producing,  115 
Infection  of  eggs,  113 
Interest  to  the  human  race,  104 
Iron,  120 
Light-producing,  115 
Milk-curdling,  114 
Milk-souring,  113 
Mineral  springs,  120 
Nitrifying,  102,  117 
Nitrogen,  117 
Nodules  of  alders,  119 
Nodules  of  alfalfa,  118 
Nodules  of  beans,  118 
Nodules  of  vetches,  118 
Number  of  in  Minnesota,  27 
Nutrition,  103 
Nutrition  of  purple,  116 
Parasitic,  453 
Producing  acetic  acid,  114 
Producing  alcohol,  102 
Producing  lactic  acid,  113 
Pitcher-plant,  279 
Purple,  116 
Putrefaction,  102,  109 
Red,  115 
Relations  of  to  man,  120 
Retting,  in 
Root-tubercle,  119 
Smallpox,  106 
Sources  of  ferments,  104 
Substances  formed  by,  103 
Substances  and  forces  harm- 
ful to,  104 
Sulphur,  120, 453 


Bacteria 

Tanning,  in 
Tobacco-curing  (see  preface),  in 

Typhus,  106 

Urine,  119 

Vinegar,  114 

Waste  products  of,  103 

Water,  443 

Bacterial  phosphorescence,  104 

Purple,  104 

Bailey's  dogwood,  341 

Ball-tossing  puff-ball,  70 

Ejection  of  spores,  71 

Balm  of  Gilead,  238,  239 

Balsam  (see  Fir),  186,  192 

Balsam  thicket,  472 

wood,  352 

-apple,  396 

-poplar,  238, 239 

Witches'-broom,  54 

Banana,  228 

Fruit,  423 

Baneberry,  268, 269 

Bar  plants  (Half-tone,  449),    447,451 

Barberry,  264, 274 

Wheat  rust,  50 

Bark-moss,  149 

Bark  of  trees,  234 

Barley,  205 

Barnyard  grass,  205 

Barrel-hoops,  244 

Barrens,  469 

Barrens,  Jack-pine,  470 

Oak,  470, 478 

Basil,  375,  377 
Bass-weed,  13,  38,  448,  451,  521 
Bass-weeds,  Lime-encrusting,  38 

Propagative  bulbils  of,  38 
Basswood,            252,  321,  423,  462,  478 

Galls,  504 

Basswood,  European,  323 

Half-tone,  324 

Bast,  497 

Bay,  275 

Bayberry,  243 

Beach,  469 
Beach  vegetation  (Half-tone),  241 

Beach  heather,  327 

peas,  304 

Beaked  hazelnut,  246 

Bean,  280,  418,  503 

Bacterial  nodules  on,  118 


530 


Minnesota  Plant  Life. 


459 
305 
478 

355 


Bean 

Buck,  363, 458 
Castor, 

Wild,  297,  304, 

Bearberry,  350, 

Beardtongue,  381 

Beck's  marigold,  411 

Bedstraw  (Engr.  389),  388 

Beech,  246 

Beech-fern,  166 

Water,  246 

Beechdrops,  385 

Beer,  Souring,  114 

Beet,  425, 491 

Beetle-fungi,  91, 99 

Spores,  100 
Beggars'-lice,  Seed  distribution,       19 

Beggar-tick,  401, 410 
Begonia,  326,  425,  507,  512 
Behavior  of  the  fecundated  egg,  523 

Bellflower,   Marsh-,  396 

Tall,  396 

Wood-,  396 

Bellwort,  225, 226 

Beltrami  county,  315 

Benzoin  gum  tree,  360 

Bergamot,  37- 

Biennial,  428 

Bignonia,  367 

Big  Stone  lake,  262 

Big  trees,  Fossil,  26 

of  California,  39 
Bilateral  symmetry  of  flowers,        228 

Bilberry,  4(5o 

Dwarf,  356 

*^     >  1  C^S 

Thin-leafed,  356 

Bindweed,  258,  367,  478 

Birch  (Half-tone,  145,  195), 

245,  246, 

-bark,  Indian  uses  of, 
beer,  Flavoring, 


Birch,  Black,  246-  24?> 

Canoe  (Half-tone,  247,  248;, 

246, 
Dwarf, 

Glandular,  24£ 

Gray,  ' 

246, 


462 
247 
24Q 

249 
24g 


247 


Birch 

Root-fungi, 
Scrub, 
Shelf-fungi, 
Yellow, 

Birds,  Habits  of, 
Bird's-eye  maple, 
Bird's-foot  violet, 
Bird's-nest-fungus, 
Bird's-nest-fungus,  Fruit-body, 
Bishop's  cap, 
Bittersweet,  „ 

Climbing, 
Black  alder, 

ash, 

ash,   Gall, 

birch, 

cherry, 

-eyed  Susan, 

fungus, 

fungus   lichens, 

haw, 

knot,   Cherry, 

knot,  Chokecherry, 

knot,   Plum, 

maple, 

mould, 

mould,  Eggs, 

mould,  Fruit-body, 

mould,  Reproduction, 

mould,   Spores, 

nightshade, 


89 
246 

57,  58 
246,  247 
18 
316 
328 
69 
/o 
284 


312,418,479 

249,  312 
'  36l 

5O4 

246,  247,  249 
2Q4 
32- 

80,  83,  95 
98 

390,  462 
85 
85 
85 
3I3>  ^ 


Paper  (Half-tone,  247), 

*ed' 
Rlver» 


246,  247 
246,247 


44 
43 
44 
44 
378 
249,250,251 

2gi 
5I 

338 

T86,  192 
243;  244 

241 

280,290,511 
291 
291 
54 

291 

309,313 
Bladderwort  (Engr.  383), 

233-367,384,418,  512 
Air  chamber,  443 

Flower,        .  384 

Hibernaculae,  451 

Nutriment,  384 

Pollination,  384,  445 

Resemblance  to  water-mil- 
foil 384 


oak, 

raspberry, 

rust, 

snakeroot, 

spruce, 

walnut, 

willow, 

Blackberry, 
High, 
Low, 
Rust, 
Swamp, 

Bladdernut, 


Minnesota  Plant  Life. 


Blazing-star   (Engr.  407), 

Bog, 

453 

401,  402,  406,  415,  470 

blueberry, 

357 

Bleeding-heart, 

277 

huckleberry, 

356 

Blephilia, 

375,  376 

plant, 

436 

Blight, 

80 

rush, 

225 

Grass, 

80 

wintergreen, 

35i 

Hooked, 

80 

Boltonia, 

401,  407 

Lilac-, 

80 

Boneset  (Engr.  407), 

373,  401 

Pear-, 

103,  109 

Borage, 

367,  371 

Toadstool-, 

80 

family, 

371 

Willow-, 

80 

Flower, 

37i 

Blinds,  Manufactured  from 

Resemblance  to  verbena, 

374 

white  pine, 

186 

Wheat   rust    on, 

50 

Elite, 

259 

Borneo  ferns, 

164 

Western, 

260 

Bottle-gourd, 

394 

Blood-root  (Engr.  276), 

275 

Box-elder,                             309, 

313,  317 

Bloodwort, 

224 

Braced-plant, 

179 

Bloom  on  fruit, 

435 

Bracken  fern  (Half-tone,  419), 

Blown  cheese, 

112 

164, 

165,  472 

Blue  ash, 

361 

Bracted  plantain, 

387 

cohosh, 

274 

Brake, 

161 

Earth  county, 

332 

Bramble,        280,  290,  439,  460, 

470,  506 

-eyed  grass, 

227,  457 

Rootstock, 

455 

-eyed-Mary, 

222 

Branch,   Drooping, 

422 

flag,                  219,  224,  227, 

457,  458 

system, 

422 

flag,  Flower, 

348 

Brazil-nut. 

322 

flax,  Wild, 

306 

Bread,   Diseases, 

112 

grass, 

205,  206 

-making,  Yeast, 

72 

-green  algae, 

Souring, 

114 

26,  29,  424,  443, 

446,  453 

Brewing   Yeast, 

72 

-green  algae,    Extraction 

of 

Bright-green  algae,             29, 

446,  522 

iron  oxide  from  water, 

3° 

-green  algae,  Lichens, 

93 

-green  algae,  Lichens, 

93,94 

Broad-leafed  aster, 

479 

-green  algae,   Lime-encrust- 

cat-tail, 

198 

ing, 

30 

goldenrod, 

479 

gum  tree,  Australia, 

434 

green  milkweed, 

367 

lobelia,    Large, 

397 

puccoon, 

O*-V 

171 

lobelia,  Pale, 

397 

Brookside  vegetation  (Half-tone, 

mould,                          44,  78,  86,  513 

366). 

honeysuckle, 

392 

Broom. 

280 

phlox, 

369,  370 

-rape, 

367,  385 

Blue-stoning, 

50 

-rape,    Louisiana, 

386 

verbena,    Wild, 

374 

Brown  algae, 

Bluebell  (Engr.  395), 

29,  513,  520,522, 

523,  525 

3/2,  394, 

396,  462 

Buck-bean,                           363, 

458,  459 

Blueberry,                             350, 

356,  470 

Buckeye, 

317 

Bog, 

357 

Buckthorn,                            319. 

459,  462 

Canada, 

356 

Alder-leafed, 

319 

Dwarf, 

356 

Wheat  rust  on, 

50 

Low, 

356,  357 

Buckwheat, 

257 

Swamp, 

457 

False, 

258 

Tall, 

356 

Bud, 

425 

Bluejoint, 

205 

Separable  of  pondweed. 

512 

Bluet, 
Blunt-leafed    milkweed, 

389 
366 

Buffalo-berry,                      332, 
Canada, 

437,  465 
333 

532 


Minnesota  Plant  Life. 


Buffalo-berry 

Silver,  333 

-grass,  205,  206,  464 

Bugle-weed,  375 

Bug,  Potato,  379 

Bugseed,  259 

Bulb,  512 

Burrowing,  21$ 

Subterranean,  426 

Bulblet-fern,  166 

Bulrush  (Half-tone,  201,  213,  421), 

i  j,  30,  38,  214,  451,  457,  459 

Air  chamber,  455 

Rootstock,  458 

Stem  structure,  422 

stem,  Three-cornered,  215 

Bunchberry,  340 

Burdock,  399,  401,  413,  415 

Involucre,  399 

Seed  distribution,  19 

Large,  413 

Small,  413 

Bur-marigold,  401, 410 

Submerged  leaves,  417 

Water,  449 

Burning-bush,  312 

Bur  oak  (Half-tone,  419),  249, 251, 478 

Bur-reed,  198 

Burrowing  bulb,  218 

Burweed,  4=58 

Bush  clover,  303 

-honeysuckle,  393 

Bushed  willows,  241 

Butter,  Diseases,  112 

"June  flavor,"  m 

-seed,  360 

Buttercup,  256,  264,  268,  475,  476 

flower,  348 

Water,  fruits,  272 

Water-,  272,  448,  417 

Water-,    Stiff,  272 

Water-,  White  (Engr.  271)       272 

Butterfly-weed,  365 

Butternut,  243, 244 

Fungus,  86 

Butterweed,  4I2 

Swamp,  458 

Butterwort,  384, 418 

Nutrition,  385 

Use  in  cheese-making,  385 

Button-bush,  388,  389 

-bush  dodder,  369 

Button-snakeroot,  338 

Butyric  acid-producing  bacteria,     102 


Cabbage,  277 

Slime-mould  on  roots,  27 

Yeast  growing  on  cooked,          74 

Cabinet-making,          193,  244,  247,  297 

Cactus,  417,  436,  437,  465,  474,  506 

Melon,  33o,  465 

Prickly-pear,  22,  468 

Prickly-pear,    Western 

(Engr.),  330 

Purple,  329 

Calamint,  375 

Calla  lily,  217,  219,  451,  458 

Callirrhoe,  323,  324 

Calopogon,  231 

Calycanthus,  275 

Calypso,  228 

Calyx,  346 

Cambium,  486 

in  trees,  234 

Camphor  plant,  326 

Campion,  263 

Canada  balsam,  192 

blueberry,  356 

buffalo-berry,  333 

plum,  293 

toad-flax,  381 

violet,  329 

Canary-seed  grass,  205 

Cancerroot  (Half-tone,  385),  385,  438 

Parasitism,  439 

Clustered,  386 

One-flowered,  386 

Canna,  228 

Canning  of  fruits,  etc.,  no 

Canoe  birch,  246,  247 

Canterbury-bell,  372,  468 

Caper,  275, 468 

Capsicum,  367 

Capsule,  Cone-headed  liverwort,     134 

Horned  liverwort,  139 

Leafy  liverworts,  141 

Liverwort,  154 

Moss,  154 

Origin  and  development  of, 

moss  and  liverwort,  130 

Caraway  seed,  340 

Care  of  the  young,  525 

Carex-sedge,  215 

Cardinal-flower,  397 

Carlton  peak,  148 

Carnation,  263 

disease,  103,  109 
Carnivorous  plants, 

278,  418,  438,  460,  481,  489 

Indian  cup,  408,  409 


Minnesota  Plant  Life. 


533 


Carolina   geranium,  305 

Carpel,  197 

Definition,  184 

Carpet-moss,  152, 459 

plant,  211 

-weed   (Engr.  261), 

24,  259,  261,  470,  476 

Carrion-fungus,  66, 67 

Carrot,  34°,  49 1 

Cass  county,  186,  221 

Cass  lake,  357 

Cassiope,  35° 

Castor-bean,  305 

-oil  plant,  511 

Casuarina  tree,  236 

Catalpa,  367, 383 

Leaves,  423 

Caterpillar  fungus,  82,  438 

Catchfly,  259, 263 

Catnip,  375, 376 
Cat-tail  (Half-tone,  12,  18), 

197,  198,  437,  457,  458,  459 

Rootstock,  455 

Broad-leafed,  198 

Cauliflower,  277 

Cecropia,  5°7 

Cedar-apple,  54 

Cedar  lake  (Half-tone),  10 

swamp,  457 

Cedar,  Red  (Half-tone,  193), 

186,  192,  193,  472 

Red,  Flower,  346 

White  (Half-tone,  189),      186,  190 

Cell,  497 

division,  498 

growth,  494 

Origin,  493 

-parasites,  45 

Reproductive,  513 

sap,  495 

Century-plant,  465,  473,  474 

Chaffweed,  350,  358,  359 

Checkerberry,  350,  355 

Cheese,  Bacterial  flora,  in 

Blown,  112 

Diseases,  113 

-making,  Use  of  butterworts 

in,  385 

plant,  323 

Ripening,  112 

Cherry,  292, 293 

Black,  294 

Black  knot,  85 

Choke-  294 
choke-,  Flowers   (Engr.),          293 


Cherry,  Dwarfed,  293 

Dwarfed,  293 

Ground-,  367,  378 

Pin-,  293 

Pocket-fungus,  74 

Sand-  (Half-tone),  292 

Sand-,  Western,  293 

Wedge-leafed,  293 

Witch's-broom,  74 

Chestnut,  246 

Horse,  309,  317 

oak,  249, 251 

Chickweed,  263 

Chicory,  399,  402 

Chisago  county,  221 

lake,  363 

Choisy's  dodder,  369 

Choke-cherry,  294 

Black  knot,  85 

Chokeberry,  286,  287,  290,  470 

Chlorophyll,  488 

Christmas-green  plants,  156 

trees   (see  spruce),  192 

Chrysanthemum  (Half-tone, 

400),  401 

Cigars,  diseases,  112 

Cigar-moss  (Lichen),  97 

Cinchona,  388 

Cinnamon  fern,  164,  173 

Citron,  394 

Clammy   ground-cherry,  378 

-weed  (Engr.  276),  275 

Classification  of  bacteria,  102 

Classes,  Higher  seed  plants,  197 

Claytonia,  262,  437 

Clearweed,  254, 255 

Clematis,  264,  268,  271,  439,  479 

Ground-,  271 

Cliff-brake,  165, 468 

Climate,  480 

Climatic  history  of  plants.  427 

Climbing  bittersweet,        312,  418,  479 

nightshade,  379 

Clintonia   (Engr.   225),  225,479 

Closed  gentian,  362 

Closets,  Moth,  193 

Clover,  280,  298,  427,  476,  503 

roots,    Bacteria,  117 

root  nodules,  117 

Clover,  Bush,  303 

Prairie,  297,  301 

Prostrate,  299 

Red,  298 

Sweet,  298 


534 


Minnesota  Plant  Life. 


Clover, Sweet,bushes  (Half-tone),  299 

White  (Half-tone,  300),  298 

Yellow,  298 

Club-fungus,  438 

Club-Moss  (Engr.  156),  156, 

469,  490,  514,  5l6,  518,  519,  520 

Cones,  157 
Cones,  Origin  of  the  flower,     343 

Life-history,  156 

Minnesota,  159 

Origin,  123 
Relation  to  horned  liverwort,  140 

Rootstock,  455 

Spore  production,  159 

Club-moss,  Flat-branched  (Engr. 

158). 

Smaller  (Engr.  159). 

Club-root,  27 

Cluster-cup  fungus,  52,  514 

Clustered  cancerroot,  386 

Coal,  Formation,  146 

Cob,  Corn,  207 

Coca  tree,  305 

Cocaine,  305 

Coccus,  102 

Cockle,  21, 259 
Cocklebur,   (Engr.  404), 

12,  399,  401,  405,  415 

Involucre,  399 

Seed  distribution,  19 

Cockscomb-grass,  n 

Cocoanut,  Fruit,  423 

Seed,  420 

Coffee,  388 

tree,  Kentucky  (Engr.  296), 

296,  297 

Cohosh,  Blue,  274 

Collomia,  369,  370 

Color,  Alpine  flowers,  425 

Origin  of  in  flowers,  426 

Polar   flowers,  425 

producing  bacteria,  102,  115 

Purple,  433, 449 

Warming-up,  36 

Warming-up,"  Peat-moss,  146 

Colts'   foot  411 

Columbine,  264, 268 

Comfrey,  371,  373 

Common  milkweed,  366 

phlox,  370 

plantain,  387 

toad-flax,  380 

yellow  pond-lily,  266,  448 

yellow  violet,  329 


Compass-plant,    401,  403,  434,  464,  471 
Rosinweed  (Engr.  411),     409,464 
Wild  lettuce  (Engr.  403),          464 
Composite  (Half-tone,  408), 

394,  399,  409,  471 

family,  402, 414 

family,  Flower-cluster,,  414 

Flower,  400, 415 

Fruit  distribution,  400 

Number  in  Minnesota,  401 

Winged   distribution,  416 

Cone,  Club-moss,  157 

Cone-flower  (Half-tone,  412),  401,  409 

Long-headed,  409 

Prairie  (Engr.  413),  413 

Cone-headed  Liverwort,  133,  518,  520 

Liverwort  Capsule,  134 

Liverwort  Spermary,  136 

Confection,  Marshmallow,  325 

Mint,  used  in,  378 

Consumption  bacteria,  106,  108 

Contagious  diseases,  106 

Cook  county,  354 

Coral-root,  228,  231,  438,  479,  490 

Root-fungus,  89 

Coriander  seed,  340 

Cork,  497 

elm,  252 

Corm,  512 

Corn-cockle,  263 

Smut,  48 

flower   (Engr.  414),  402,  413 

Indian  (Half-tone,  207),      205,  206 

Indian,  hybrids,  207 

cob,  207 

ear,  207 

husk,  207 

stalk,  431 

tassel,  207 

salad,  393, 394 

Squirrel,  276 

Cornel,  336 

Alternate-leafed,  342 

Dwarf  (Engr.  341), 

340,  342,  416,  428 

Silky,  341 

Corpse-plant  (See  Indian-pipe),  350 
Coteau,  Prairie  scene  (Half-tone),  9 
Cotton-grass,  146,  213,  457,  460 

Cottonwood  (Engr.  238.    Half- 
tone, 235,  452,  474),          238,  239,  462 
Life-history,  183 

Seed  distribution,  20 


Minnesota  Plant  Life. 


535 


Counterpoise  area,  Duckweed,      444 

Salvinia,  444 

Water-hyacinth,  444 

County,  Aitkin,  309 

Anoka,  327 

Beltrami,  3^5 

Blue  Earth,  332 

Cass,  186, 221 

Chisago,  221 

Cook,  354 

Goodhue,  325 

Pipestone,                      33°,  359,  468 

St.    Louis,  146 

Stearns,  341 

Sherburne,  327 

Winona,  356,  393 

Wright,  327 

Cowbane,  338,  340 

Cowberry,  356, 357 

Cowslip  (Engr.),  268 

Cow-parsnip,  338 

Cow-wheat,                         379,  383,  385 

Nutriment,  383 

Coxcomb,  259, 260 

Crab-apple,  286 

Wild,  286 

Cranberry, 

22,  146,  350,  356,  357,  424,  457,  460 
Position  of,  349 
Resemblance  to  partridge- 
berry,  389 
Rootstock,  455 
High  bush  (Engr.  390),  390,  41 5 
Mountain,  356 
Small   (Engr),  357 
Creeping-charley,  323 
Creeping  raspberry,  291 
resemblance  to  violet,  291 
Cress,  Rock,  275,  278 
Water  (Engr.  277),  275,  278 
Crocus,  264, 268 
Crop-rotation  and  bacteria,  118 
Cross-fecundation,  517 
-pollination,  230,  517 
Crowberry,          309,  437,  457,  459-  460 
family,  309 
Resemblance    to    yew,  309 
Crowfoot,  268 
family,  264 
Musk,  393 
Water,  Submerged  leaves,         417 
Cubeb,  236 
Cucumber,  394,  395 
-rot,  103,  109 


Cucumber,  Star-,  394,  395 

Wild,  394,  396,  439 

Cudweed,  401 

Cultivated  field,  476 

Cup-fungus,  72,  76,  95,  438,  514 

Distinguishing  characters,          77 

Spores,  77 

Tamarack,  78 

Moss,  150 

Cuplets,  Umbrella-liverwort,  137 

Curly-leaved  dock,  258 

maple,  315, 3*6 

Currant,  283, 284 

Seed  distribution,  19 

Flowering,  284 

Indian,  392 

Red,  284 

Skunk,  284 

Wild  black,  284 

Cut-leafed  ground-cherry,  378 

nightshade,  378 

Cycad,  520,  522,  524 

Fossil,  26 

Cyperus-sedge,  213 

Cypress  knees,  455 

Dairy,  Bacteria,  in 

Daisy,  407, 4*5 

Oxeye,  476 

Dandelion, 

399,  402,  415,  429,  433,  480,  509 

family,  402 

flowers  (Half-tone),  401 

fruits    (Half-tone),  402,  441 

parachute,  400 

Position  of  415 

Relatives  of,  402 

Seed  distribution,  21 

Dandelion,  Autumn,  403 

Dwarf,  403 

Dead-nettle,  375 

Deadly  nightshade,  378 

Death   of  an   organism,  484 

Deerberry,  356 

Definitions,  123,  181,  182,  183,  184 

Albumen,  183 

Alternation  of  generations,      123 

Carpel,  184 

Embryo-sac,  180,  184 

Flower,  184 

Ovule,  180,  184 

Pollen-grain,  181,  184 

Pollen-tube,  182 

Seed,  180,  184 

Seed-coat.  182 


536 


Minnesota  Plant  Life. 


Definition,  Stamen,  181,  184 

Stigma,  181,  184 

De-nitrifying  bacteria,  102,117 

Deposition  of  silica,  Scouring- 

rush,  175 

Desert  plant, 

418,  428,  436,  442,  463,  481,  506 

Leaves,  464 

Odor,  437,  465 

-succulent,  474 

Desmanthus,  296, 297 

Desmid,  34, 443 

parasites,  45 

Diatom,  39,  443,  453,  505 

Deposition  of  silica,  40 

parasites,  45 

Disc-alga,  Relation  to  liverwort,    129 
fungus,  78,  95,  514 

Disease,  Immunity  to,  106 
-producing  bacteria,     102,  103,  105 

Diseases,  Animal,  109 

Bacteria,  109 

Bread,  112 

Butter,  112 

Carnation,  103,  109 

Cheese,  113 

Cigar,  112 

Contagious,  106 

Egg,  112 

Grain,  50 

Grape  vine,  46 

Ice-cream,  13 

Infectious,  106 

Invasive,  106 

Meat,  H3 

Milk,  II2 

Plant,  iog 

Potato,  46 

Vegetable,  ^3 

Distribution,  Carrion-fungi  spore,  66 

Morel  spore,  75 

Plant,  5 

Seed,  344)  4l6 

Spermatozoid,  520 

Spore,  344)  SI4 

Winged  composites,  4i6 

Ditch-moss,  203 

stone-crop,  282 

Dock,  257,  258 

Curly-leaved,  258 

Golden,  258 


Dock,  Prairie, 
Red-veined, 
Swamp-, 
Yellow, 
Water, 


409 
258 

258,  458 
258 
258 


Dodder  (Half-tone,  368),  233,  367,  368 

Nutrition,  368,  369 

Parasitism,  369,  439 

Sucking  organs,  369 

Aster,  368 

Button-bush,  369 

Choisy's,  369 

Field,  368 

Goldenrod,  368 

Gronovius,  369 

Hazel,  369 

Massive,  369 

Smartweed,  369 

Sunflower,  368 

Dog's-tooth  violet  (Engr.  225), 

225,  226 

Dogbane,  360,  364 
Resemblance  to  flowering 

spurge,  308 
Resemblance  to  milkweed,       364 

Dogwood,  12,  332,  336, 

340,  342,  428,  459,  460,  462,  472,  478 

Position  of,  349,  415 

Dogwood,  Bailey's,  341 

Dwarf,  336 

Flowering,  340, 416 

Poison,  310,  506 

Rough-leafed,  341 

Round-leafed,  341 

Silky,  428 

Smooth-leafed,  428 

Doors,  Manufactured  from  white 

pine,  186 

Doorweeds,  258 

Douglas  county,  221 

Downy-leafed  arrowwood,  391 

phlox,  369,  370 

Dragon's-head,  375,  376,  377 

-head,  False,  376 

Duckweed,  220^436,449 

Air  chamber,  443 

Counterpoise  area,  444 

Pollen  distribution,  282 

Pollination,  445 

Duckweed,  Ivy-leaved,  220 

Smaller,  220 

Three-cornered,  220,444 

Three-pronged,  133 


Minnesota  Plant  Life. 


537 


Duluth, 

259,  262,  266,  284,  332,  354,  355,  357 
Rock-vegetation  near  (Half- 
tone), 189 
Dune,                                                    469 
-grass,                                             211 
Dung-moss,  139 
Dutchman's-breeches,               275, 276 
Dutchman's-pipe,                               256 
Root-fungi,  89 
Dwarf  shrubs,                                    428 
Dwarf  alder,                                      319 
bilberry,                                         356 
birch,                                              459 
blueberry,                                      356 
cherry,                                            293 
cornel,                     340,  342,  416,  428 
dandelion,                                      403 
dogwood,                                       336 
ginseng,                                 336, 337 
horse-tail,                                       179 
snowberry,                                     428 
willow,                                            428 
Ear,  Corn,                                          207 
-fungus,  90 
Earth-star,  68 
Spore  distribution,  69 
Easter   lily,                          224,  513,  524 
Ebony  tree,                                         360 
Economic  importance,  Algae,          41 
Ergot,  82 
Lichens,  97 
Liverworts,                                    143 
Edible  fungus,                           63,  65,  76 
lichens,                                           98 
morels,  75 
mushrooms,                                   61 
pore-fungi,  58 
reindeer  moss   (Lichen),             98 
seaweed,                                         41 
Western  prickly-pear  fruit,        330 
Eel-grass,                              197,  202,  263 
282,  448,  449,  450,  451,  452 
Holdfast,                                      447 
Egg,                                      512,  513,  52i 
Diseases,                                       112 
Fecundated,                                 513 
fecundated,    Behavior   of,          523 
Fecundated,  of  higher  ani- 
mals,                                         128 
Fecundated,  of  higher  plants,    128 
Infection  with  bacteria,             113 
production,                                    521 
Spermatozoid  directed  to- 
ward,                                         499 


Eggs,  Bass-weed 
Black  mould, 
Desmid, 
Red  algae, 
Sphere-algae, 

Elater,  Liverwort, 

Elder, 
bush, 


38 
44 
34 
40 

37 

135,  140,  515 

388,  390 

390 


Resemblance  to  wild  elder,  337 

Box-,                               309,  313,  317 
Poison,                           310,311,312 

Wild,  336 
Wild,  Resemblance  to  elder 

bush,  337 
Electricity,  Adaptations  of 

plants  to,  437 

Ellisia,  37i 
Elm  (Half-tone,  10,  14,  429), 

234,  243,  251,  252,  462,  478 
Leaves,  430 
Seed  distribution,  20 
woods,  6 
American  (Engr.  251.     Half- 
tone, 252),  252 
Cork,  252 
Red,  252 
Rock,  252 
Slippery,  252 
Three-leaved,  307 
White,  252 
Embryo,  523 
-sac,  Definition,                   180,  184 
-sac,    Germination,  518 
Enchanter's  nightshade,  335 
Energy  produced  by  bacteria,  104 
Ensilage,  Souring  of,  114 
Erect  habit  of  plants,  130 
Ergot,  81 
Economic  importance,  82 
tubers,   Poisonous,  82 
Rye,  81 
Wild  rice,  81 
Eucalyptus,  332 
Australian,  39 
Euglena,  499 
Nutrition,  445 
Plant  or  animal,  445 
European  basswood,  323 
puccoon,  373 
verbena,  374 
Evening-primrose, 

332,  334,  426,  429,  468,  470,  478 

Shrubby  prairie,  335 

White,  335 


538 


Minnesota  Plant  Life. 


Evergreen  plants,  428 

Everlastings,  401, 4°7 

Extract,   Mint,  378 

Eyebright,  Parasitism,  383 

Fairy's   spears,  210 

False  acacia,  301 

beechdrops  (see  pine-sap),        350 

buckwheat,  258 

dragon's-head,  376 

gromwell,  371,  373 

heather,  326 

indigo,  297 

indigo,  Herbaceous,  298 

indigo,   Large,  300 

indigo,  Low,  301 

indigo,  Shrubby,  300 

indigo,  White,  298 

loosestrife,  334,  358 

mallow,  323 

mermaid,  309 

nettle,  254 

pennyroyal,  376 

pimpernel,  379 

rue-anemone,                  .  268 

Solomon's  seal,  225,  226 

Family,  198 

Farina  grains,  491 

Febrifuge,  242 

Fecundated  egg,  513 

Behavior  of,  523 

Fecundation,  517, 522 

Cross-,  517 

Scouring-rush,  178 

Fence  poles,  Manufactured  from 

tamarack,  191 
Fencing   lumber,    Manufactured 

from  white  cedar,  190 

Fennel,  Hog-,  338 

Water-,  3O8 

Ferment,  103 

-producing  bacteria,     102,  109,  453 

Fermentation,  73 

of  wine,  Yeast  in,  72 

Fern  (Half-tone,  165,  455), 

161,  468,  472,  476,  490,  496, 
512,  513,  514,  5i6,  518,  519,  520 

Distinctive  features,  174 

embryo  (Engr.),  -169 

leaves,  161,  170 

Number  in  Minnesota,  27 

Nutrition,  48 

Ordinary,  jg^ 

Origin,  I23,  174 

Sexual  plant  (Engr.)  168 


Fern,  Spore-case   (Engr.),  171 

Adder's-tongue  (Half-tone),     162 
Beech,  166 

Bracken,  164,  165,  472 

Borneo,  164 

Bulblet,  166 

Cinnamon,  164,  173 

Clayton's  (Engr.  164.  Half- 
tone, 167),  167 
Cliff-brake  (Engr.),  166 
Filmy,  164 
Floating,  164,  168,  220 
Floating,  Alga  in  leaves,  169 
Floating,  Root-caps,  220 
Flowering,  164 
Forking,  164 
Grape,  161 
Interrupted  (Engr.  164. 

Half-tone,  167),  164 

Lady   (Half-tone,   173),  165 

Maiden-hair  (Engr.  170.  Half- 
tone, 173),  165 
Ostrich,  166 
Ostrich,  Leaves,  173 
Perching,  472 
Polypody  (Engr.),  170 
Royal,  165 
Sensitive  (Half-tone,  165),  166 
Shield-  (Half-tone,  167),  166,  459 
Sweet-,  242, 460 
Tree,  164 
True,  163, 496 
Twining,  164 
Virginia  grape-  (Engr.),  163 
Walking  (Half-tone,  172),  165 
Water-, 

161,  444,  506,  5i5,5i6,  519,  520 
Water-,  Four-leafed  (Engr. 

168),  164,166,  173,448,518 

Fertilizer,  Algae,  41 

Fescue  grass,  205 

Fever  plants,  Hay,  405 

Feverwort,  391 

Fibre,  Flax,  306 

Field,  Cultivated,  476 

dodder,  368 

horse-tail,  178 

Fig,  251 

Figwort,  367,  379,  381 

Resemblance  to  lobelia,  397 

Resemblance  to  mint,        379,  397 

Filmy  fern,  164 

Fireweed,  334, 412 


Minnesota  Plant  Life. 


539 


Fir,  186 

Flower,  347 

Seed    distribution,  20 

Firewood,  Jack  pine,  oak,  tam- 
arack, white  poplar, 

190,  191,  238,  250 

First-stage,  Liverwort,  124,  128 

Moss,  124,  128,  151 

Fish-mould,  45,  513,  515 

Life-history,  46 

parasites,  45 

Spermatozoids,  46 

Fivefinger,  289 

Resemblance  to  anemone,         290 
Marsh,  289 

Flag,   Blue    (Half-tone,    12, 225, 

226,250),  219,224,227,437 

Blue,  Flower,  348 

Sweet  (Half-tone,  12),       219,437 

Flax,  305,  306,  475 

seed,  306 

Flax,  Grooved  yellow,  306 

Stiff  yellow,  306 

Toad-,  380, 438 

Wild  blue,  306 

Fleabane,  401,  402,  407,  469 

Flesh-eating  fungus,  58 

Fleur-de-lis  (see  blue  flag),  227 

Floating  leaves,  449 

arrowhead,  448, 449 

fern,  164,  168,  220 

fern,  Alga  in  leaves,  169 

fern,    Root-caps,  220 

-heart,  364 

liverworts,  132 

marsh-marigold,  268 

Riccia,  443 

Flooring,    Manufactured  from 
sugar  maple,  316 

Flora,   North  America,  16 

Florida  milkweed,  367 

Flower,  414 

Alpine  colors,  425 

Autumn,  426, 479 

axis,   Development,  345 

axis,   Anemone,  345 

axis,    Mousetail,  345 

axis,   Rose,  345 

axis,  Strawberry,  345 

Bilateral  symmetry,  228 

Closing  of  at  night,  427 

-cluster,  Development,  414 

-cluster,  Composite  family,      414 
Definition,  184, 346 


Flower,  Development,  343 

Irregularity,  348 

High  types,  343 

Law  of  variation,  343 

Low  types,  343 

Origin,  343,  440 

Spring,  426, 479 

Perfect,  321 

Polar  colors,  425 

Prototype  of,  343 

Radial  symmetry,  228 

Sleep-position,  427 

Typical,  Definition  of,  346 

Typical  Development  of,  346 
Why  one  of  higher  type  than 

another,  349 

Passion,  326 

-of-an-hour,  325 

-pot   alga,  35 

Spider,  275 

State,  231 

Flowering  plant,  490,  514,  516,  518,  520 

Honey  secretion,  515 

Number  in  Minnesota,  27 

Nutrition,  48 

Origin,  174 

Planktonic,  445 

Flowering-currant,  284 

dogwood,  340, 416 

fern,  164 

Spurge,  308 

Flowering  Spurge,  Resemblance 

to  dogbane,  308 

Fly-cholera  fungus,             45,  438,  514 

honeysuckle,  392 

Fogfruit,  373,  374 

Food-material,  Reserve,  426 
Partnerships  for  obtaining,       489 

Plant,  488, 489 

Storage,  490 

Disposal,  4Qi 

Forage  plants,  21 

Forces  harmful  to  bacteria,  104 

Forest  (Half-tone),  7 
Dominant  plants,  7 
and  prairie,  Difference  be- 
tween, 8,  14 
Hardwood  (Half-tone,  480), 

252,  475,  478 

horse-tail,  178 

Minnesota,  6,  12 

Pine,  472 

Forget-me-not,  371, 372 


540 

Forking  fern, 
Formation  of  coal, 

of  peat-bog, 
Fossil   cycad, 

diatoms, 

plants, 

seaweeds, 
Four-leafed  milkweed, 

water-fern,      164,  166, 

water-fern,  Leaves  of 
Four-o'clock, 
Fox-glove, 
Fox-grape, 

-tail  grass, 
Fragrant  sumac, 
Fringed  gentian, 

Houstonia, 
Frost-grape, 
Frostweed, 
Fruit,  Bloom  on, 

canning  of,  etc., 

Heavy, 

Structure, 

Fruit,  Agrimony, 

Apple, 

Avens, 

Banana, 

Blackberry, 

Cherry, 

Cocoanut, 

Fivefinger, 

Gourd, 

Hawthorn, 

Liverwort, 

Moss, 

Mountain-ash, 

peach, 

Pear, 

Plum, 

Pumpkin, 

Raspberry, 

Rose, 

Spiraea, 

Squash, 

Strawberry, 
Fruit-body,    Bird's-nest 

Black  mould, 

Blight, 

Carrion-fungus, 

Caterpillar  fungus, 

Morel, 

Mushroom, 

Peat-moss, 


164 

146 

146 

26 

39 

26 

26 

366 

173,  448,  518 

166 

259,  261 

367 
321 
476 
310 
362 
390 
321 
326 
435 
no 
422 
420 
295 

295,  423 
295 
423 
295 
295 
423 
295 
423 
295 
123 
123 
295 
295 
295 
295 
423 
295 

292,  295 

295 

423 

295 

fungus,      70 

43 
80 

67 
82 

75 

63 

147 


Minnesota  Plant  Life. 

Fruit-body,  Reindeer  moss,  97 

Slime-mould,  28 

Smut,  48 

Fruit-cluster,  416 

Fruit  distribution,  Snakeroot,          339 

distribution,  Sweet  cicely,         339 

Fuchsia,  334, 436 

Fuel,  Cottonwood,  239 

Sugar-maple,  316 

Fuller's-teazel,  388 

Fumitory,  12,  275,  277 

Golden,  277 

Pale,  277 

Yellow,  277 

Fungus,  22,  488,  489,  506, 

512,  513,  519,  522,  523 
alkaloids,  82 

Edible,  63,  65,  76 

Growing  in  darkness,  429 

Life  of  a,  87 

Number  of  species  in  Minne- 
sota, 27,  43 
Nutrition,  48, 87 
Origin,  88 
Parasitic,  49,  74,  98,  438,  506 
Poisonous  in  tamarack 

swamps,  59 

Reproduction,  87 

Spores  produced  in  sacs,  72 

Spores  produced  on  stalks,        72 
Starch-manufacture,  48 

Algal,  43 

Algal,  Parasitic,  45 

Beetle-,  91, 99 

Beetle,  Spores,  100 

Bird's-nest,  69 

Bird's-nest,    Fruit-body,  70 

Black,  80,  83,  95 

Butternut,  86 

Carrion-,  66, 67 

Caterpillar,  82, 438 

Club-  (Half-tone,  56),          55,  438 
Cluster-cup,  5*4 

Cup-    (Half-tone,   76), 

72,  76,  95,  438,  514 


Cup,  Tamarack, 

Disc-, 

Ear-, 

Flesh-eating, 

Fly-cholera, 

Higher, 

Leaf-spot-, 

Lichen-, 


78 

78,95,514 
90 
58 

45,  438,  5H 
48 

83,84 
95,  5i8 


Minnesota  Plant  Life. 


Fungus,    Pine-knot,  54 

Pocket-  (Half-tone),  74 

Pore-,  (Half-tone,  59,  60),  57 

Pore-,   Edible,  58 

Pore-,  Oak  tree,  58 

Pore-,   Poisonous,  82 

Pore-,  Sulphur-colored,  58 

Prickle,  56 
Root,                                         80, 88 

Root,   Birch,  89 

Root,   Coral-root  orchid,  89 

Root,  Dutchman's  pipe,  89 

Root,    Oak,  89 

Root,   Orchid,  89 

Root,  Pyrola,  89 

Root,  Tamarack,  89 


Sac-, 


72,  74,  80,  95,  513 


Shelf-  (Half-tone,  57),  57 

Shelf  Toadstool-like,  59 

Shelf,   Birch,  58 

Shelf,  Poisonous,  59 

Skin-,  55 
Spot-disease  (Half-tone), 

82,  83,  84,  85,  86,  87 

Staghorn,  86 

Stalk-,  95 

Tar-spot,  Maple,  78 

True,  43, 48 

True  Parasitic,  48 

Trembling,  55 

Twig-  (Half-tone,  88),  85 

Furniture,  Manufactured  from 

basswood,  323 
Manufactured  from  butternut,  244 
Manufactured  from  red  or 

river  birch,  247 
Manufactured  from  soft 

maple,  315 
Manufactured  from  sugar 

maple,  316 

Gall,  361,  504 

Gamete,  512 

Gas    bubbles,    Water    flower,  29 

bubbles,  Algal  plankton,  443 

Gaura,  335 

Scarlet,  335 

Gemma  propagation,  Origin,  138 

Moss,  150 

Umbrella-liverwort,  137 

Gentian,   6,  360,  362,  426,  459,  462,  475 

Closed,  362 

Fringed,  362 
Horse-,                                   388,  391 


Gentian,   Oblong-leafed,  362 

Narrow-leafed,  363 

Red-stemmed,  363 

Soapwort,  363 

Spurred,  363 

Stiff,  362 

Yellow  (Engr.  362),  363 

Geranium,  305, 432 

Carolina,  305 

Spotted-leafed,  305 

Gerardia,  379,  382 

Germination,    Spore,  518 

Spore,   Scouring-rush,  177 

Gesnera,  367 

Giant  kelp,  513 

lily  of  the  Amazon,  433 

puff-ball,  69 

Gilia,  369,  370 

Ginseng   (Engr.   337),  336 

root,  337 

Dwarf,  336, 337 

True,  337 

Glade-mallow,  323,  325 

Gland,  465 

Glandular  birch,  246,  247 

Glasswort  (Engr.  259), 

259,  436,  437,  473,  474 

Glenwood  lake,  38 

Gloxinia,  367 

Golden  dock,  258 

fumitory,  277 
Goldenrod  (Half-tone,  309,  408, 
410),    6,   9,    399,   401,    402,    406, 

426,  427,  430,  469,  478,  479 

dodder,  368 

Early  (Engr.)  409 

Golden  root,  268 

saxifrage,  283 

Goldthread,  264, 268 

Goodhue  county,  325,  393 

Gooseberry,  280,  283,  284 

Seed  distribution,  19 

Prickly,  284 

rust,  54 

Goosefoot,  259 

Salt-loving,  473 

Gosling,  268, 271 

Gourd,  395,  427,  503 

family,  394 

family  fruit,  423 

Flower,  394 

Seed  distribution,  19 

Grain,  421 

disease,  50 


542 


Minnesota  Plant  Life. 


Grain  Grass,  204 

Grand  Marais,  3.29 

Grand  Rapids  (Half-tone),      145,  212 
Granite  lake  rapids,  281 

Granite  moss,  148 

Granitic  region  vegetation,  463 

Grape  (Half-tone,  320),    319,  427,  439 
disease,  46 

Mildew,  46 

Grape,  Fox-,  321 

Frost-,  321 

Riverside,  321 

Summer,  321 

Wild,  320,  418,  479 

Wild,  Resemblance  to  moon- 
seed,  320 
-fern,  161 
Grass  (Half-tone,  10, 12, 18,471),  7, 
12,  198,  204,  430,  459,  460,  464,  465, 
468,  470,  471,  475,  476,  478,  480,  502 
Dominant  prairie  plants,  7 
Grain  of,  204 
Grain  distribution,  210 
Position  of,  349 
Resemblance  to  sedge,  212 
Spikelets,  204 
Varieties,  2C,6 
Alkali-,  226 
.Barn  yard  (Engr.),  205 
Beard  (Engr.),  205 
Beckman  (Engr.),  206 
blight,  80 
Blue,  205, 206 
Blue-eyed,  227, 4.57 
Buffalo,  205,  206,  464 
Canary-seed,  205 
Cockscomb-,  n 
Cotton-  (Half-tone,  212), 

146,  213,  457,  460 

Dune-,  211 

Eel-  (Engr.  202), 

263,  282,  448,  449,  450,  451,  452 
Eel-,  Holdfast,  447 

Fescue,  2O5 

Fox-tail,  476 

Kalm's  brome-   (Engr.),          209 
Knot-,  11,258 

Mat-,  2II 

Millet,  Smut,  4g 

Muhlenberg  (Engr.),  206 

Panic,  205 

PePPer,  275, 278 

-pink,  23I 


Grass,  Prairie  (Half-tone,  471),      437 
Reed-    (Half-tone,   213), 

13,  205,  206,  451,  457,  458,  459 

Rib,  387 

Salt-loving,  473 

Sand-binding,  205, 211 

Sand-loving,  J2 

Spear,  210 

Star-,  227 

Star-,  Water,  217,  222 

Tumbling,  205,206,211 

Tumbling,  Seed  distribution,      21 

Whitlow-,  275, 278 

Yellow-eyed,  221,  457 

Gravity,  Influence  on  plants,  418 

Gray  birch,  246 

willow,  241 

Great  lakes  region,  238 

Greek  valerian,  369 

Green    plants,  488 

Green  alder,  249 

ash,  361 

felt,  37,493,515 

-flowered  wintergreen,  351 

milkweed,  367 

mould,  44,  78 

slime,  426 

Grindelia,  406 

Gromwell,  False,  371 

Gronovius'    dodder,  369 

Grooved  yellow  flax,  306 

Ground-cherry,  367,  378 

Clammy,  378 

Cut-leafed,  378 

Long-leafed,  378 

Low,  378 

Philadelphia,  378 

Virginia,  378 

-clematis,  271 

-hemlock,  185,  194,  468 

-pea,  280 

-plum,  298,  302 

tomato,  378 

Groundnut,  304, 336 

Groundsel,  412 

Marsh,  412 

Growth,  43o,  488,  491 

Cell,  494 

Living    substance,  492 

Organs,  495 

Tissues,  495 

Movements,  500 

Gul1  lake>  353,  354 


Minnesota  Plant  Life. 


543 


Gum-plant, 

406 

Hemlock,  Ground-,                    194,  468 

tree,  Benzoin, 

360 

Poison-,                                 338,  339 

Gutta-percha, 

360 

Water-    (Engr.   340),                  338 

Habit  of  plants,  Erect, 

130 

Hemp,                                         251,  253 

Hackberry,                           251,  252, 

253 

-nettle,                                            376 

Leaves, 

430 

Water-,                                   259,  261 

Hairy-capped  moss,           151,459, 
honeysuckle, 
milkweed, 
Halberd-leafed   rose-mallow, 

472 
392 
366 

Hen-and-chickens,                     282,  474 
Hepatica,                                      268,  269 
Herbs  and  trees,  Comparison,      234 
Hickory  (Half-tone,  244), 

243,  244,  245 

323, 

325 

Seed   distribution,                         20 

violet, 

329 

Pignut,                                   243,  244 

Halophyte, 

473 

Shell-bark,                             243,  244 

Hard  maple, 

313 

Swamp,                                  243,  244 

-skinned   puff-ball, 

70 

White,                                            243 

Hardening  of  cider,  Yeast, 

72 

High  blackberry,                                291 

Hardwood   forest,              252,  475, 

478 

bush   cranberry,           388,  390,  415 

Hare's-ear, 

338 

Higher  plants,     513,  514,  520,  523,  525 

Harebell, 

396 

plants,  Comparison  with 

Haw,  Black,                               390, 

462 

lichens,                                           98 

Hawk's-beard, 

403 

plants,  Division  of  labor,          490 

Hawk  weed,                                  402, 

403 

plants,   Nutrition,         103,  118,  119 

Hawthorn  (Engr.  287), 

plants,  Origin,                       129,  196 

286,  287,  290,  478, 

506 

plants,    Origin   of  root,             157 

Hay-fever  plant, 

405 

plants,  Origin  of  seed,               160 

Hazel,                                            245, 

246 

seed  plants,                            197,  517 

scrub, 

477 

seed  plants,   Characters,             197 

dodder, 

369 

Hoary  puccoon,                                  372- 

Witch-                            274,  280, 

284 

verbena,                                         374 

Hazelnut,   Beaked, 

246 

willow,                                    241,  242 

Heal-all, 

3/6 

Hog-fennel,                                          338 

Heart-leafed  plantain, 

387 

Holly,                            309,  312,  462,  465 

willow,                                    241, 

242 

Mountain,                                     312 

wintergreen, 
Heat-producing  bacteria,         102, 

351 
H5 

Hollyhock,                                   321,  323. 
Honewort,                                           338 

Heath,                                      6,  146, 

Honey,  Secretion  in  flowering 

437,  457,  459,  460,  465, 

472 

plants,                                                515. 

Resemblance  to  partridge- 

-locust,                                           280 

berry, 

389 

Honeysuckle,                               392,  428 

Rootstock, 

455 

family,                                     388,  390- 

bush, 

469 

Blue,                                               392 

Lichen, 

469 

Bush-,                                           393, 

Moss, 

468 

Fly-,                                              392 

Heather,  Shrubby, 

469 

TT      • 

Hairy,                                             392 

Beach   (Engr.   327), 

327 

Involucred,                                    393 

False, 

326 

Mountain-,                                    392 

Hedge,                                     -    190, 

241 

Smooth,                                         392- 

-hyssop, 

38i 

Sullivant's,                                      392 

-mustard, 

278 

Swamp,                                   392,  393 

-nettle,                                    375, 

376 

Yellow,                                           392- 

Hellebore,                                    225, 

226 

Hooked  blight,                                   80 

Hemlock,                                    186, 

190 

Hop,                             251,253,439,479 

bark, 

191 

Medicinal  value,                          253. 

544 


Minnesota  Plant  Life. 


Hop  tree,  3O7 
-hornbeam  (Half-tone,  245), 

245,  246 

Hornbeam,  246 
Horned  liverwort,  139 
liverwort,   Relation  to  club- 
moss,  14° 
Hornwort,  264, 267 
Horse-chestnut,  309,  3*7 
family,  3*7 
gentian,  388,  391 
-tail  (Engr.  176),  175 
-tail,  Minnesota,  178 
-tail,  underbrush  habits,  179 
Horse-tail,   Dwarf,  179 
Field,  1/8 
Forest,  178 
Water,  178 
Horsemint,  375,  376,  377 
Hot  spring,  424 
spring  algae,  31 
spring  vegetation,  453 
Hound's-tongue,  37i 
Houstonia,  388, 389 
Fringed,  39° 
Long-leaved,  390 
Huckleberry,  350,   357 
Bog,  356 
Squaw,  356 
Hudsonia,  327 
Humus,  438, 459 
plants,  479, 489 
Husk,  Corn,  207 
Hybrids,  Indian  corn,  207 
Hydrangea,  280 
Hydrophyte,  442 
Modified,  453 
Hydrophytic  vegetation,  462 
Hyssop,  367,  375,  377 
Ice-cream,    Diseases,  113 
Ice-plant,  259 
Immunity   to   disease,  106 
India-rubber  tree,  251 
Indian   corn,  205,  206 
corn  hybrids,  207 
corn,  Smut,  48 
cup,  408, 409 
currant,  392 
lotus,  264,  267,  452 
pink,  379, 382 
-pipe,                      350,  352,  438,  479 
-pipe,  Resemblance  to  pine- 
sap,  353 
plantain,  412 


Indian  reservations,  379 

rice   (see  wild  rice),  205 

tobacco,  407 

tobacco   lobelia,  398 

turnip,  217,  300 

uses,    Birch-bark,  247 

Indigo-plant,  280 

False,  297 

Infectious  diseases,  106 

Inoculation,  107 

Insect  pollination  of  orchids,          229 

pollination  of  pipe-vine,  257 

Insects,  20 

Instinct  of  self-preservation,  510 

International  boundary, 

281,  309,  322,  356,  357,  362 
Interrupted  fern,  164 

Introduced   plants,  u 

Invasive  diseases,  106 

Involucre,  399 

Burdock,  399 

Cocklebur,  399 

Involucred  honeysuckle,  393 

Iodine,  Manufactured  from  algae,    41 
Iris  (See  blue  flag),  220,  224 

Iron,  102 

bacteria,  102 

bacteria  and  iron  ores,  120 

oxide,   Extraction  by  algae,       30 
Ironweed,  401, 405 

Ironwood  (Half-tone,  245),     245,  246 
Irritable  behavior,  Living  sub- 
stance, 498 
behavior,  Plant  organs,  500 
Irritability,                                   488, 497 
Islands  in  Lake  of  the  Woods 
(Half-tone),                                7, 468 
in  Mississippi  river  (Half- 
tone), 14 
Isle  Royale,                                       329 
Ivy,                                                432,  502 
Poison  (Engr.  311), 

309,  310,  3H,  506 
-leaved  duckweed  (See  three- 
cornered  duckweed),  220 
Jack-in-the-pulpit  (Half-tone, 
431),       .      197,  217,  218,  219,  450.,  479 
Leaves,  43° 
Parasitic  alga,  37 
Tack-pine,                                    186, 470 
Jack-pine-barren,                                470 
Economic  importance,               190 
Jasmine,                                                360 


Minnesota  Plant  Life. 


545 


Jelly,  Made  from  silver  buffalo- 
berry,  333 
Jimson-weed,                                       379 
Joe-pye  weed  (Half-tone),  406 
Joint-rush  (See  scouring-rush),      175 
Jointweed,                                    258, 335 
Judas-tree,  296 
June-berry,                    280,  286,  287,  290 
Alder,  287 
Round-leafed,  287 
"June  flavor"  of  butter,  in 
Juniper    (Half-tone,    189), 

1 86,  192,  194,  462,  468,  469,  470,  472 

Flower,  346 

Seed   distribution,  19 

Juniper   cedar-apple,  54 

Kalnrs  lobelia,  39$ 

Kalmia  (Half-tone,  354),  354,  457,  460 

Resemblance  to  rosemary,       354 

Kelp,  Giant,  39,  5^3 

Kentucky  coffee-tree,  296,  297 

Ketmia,  323,  325 

Kettle  river,  355,  357 

Kidney-leafed  violet,  329 

Kinnikinic,  341 

Use  of  by  Indians,  342 

Knot-grass,  11,258 

Knotweed,  258 

Koch's  lymph,  108 

Labrador  tea,  350,  353,  456,  460 

tea,  Narrow-leafed,  353 

violet,  329 

Laburnum,  280 

La  Crosse,  267 

Lactic  acid-producing  bacteria, 

102,  113 

Lady-fern,  165 

Lady's-slipper,  228,  232,  342,  525 

Yellow  (Half-tone),  229 

Lake  vegetation  (Half-tone), 

18,  199,  201,  213,  380 

Lake  Alexandria,  267 

Benton,  370 

Big  Stone,  262 

Calhoun  (Half-tone,  245,  324, 

40i),  267 

Cass,  357 

Cedar    (Hall-tone),  10 

Chisago,  363 

Glenwood,  38 

Granite  lake  rapids,  281 

Great  lakes  region,  238 

Gull,  353, 354 


Lake  of  the  Isles  (Half-tone),  18 
Michigan,  Limestone  pebbles,  41 
Mille  Lac,  259 

Minnetonka  (Half-tone,  252), 

29,  267 

Osakis,  267 

Pepin,  267,  281,  355 

Red,  304 

Rainy,  190,  194,  327,  469 

Saganaga,  96, 469 

Superior,        259,  283,  284,  303,  309 
321,  322,  332,  356,  358,  363,  384 
White   Bear,  267 

of  the  Woods  (Half-tone,  7, 
241,248),  7,  29,  194,  242,  253, 
266,  304,  322,  327,  332,  356,  363, 

461,  469 

Lamb-lettuce,  388, 393 

Lance-leafed  violet,  329 

Land  plants,  Parasites,  46 

plants,  Zonal  distribution,          10 

Large  blue  lobelia,  397 

burdock,  413 

cranberry,  356, 357 

false   indigo,  300 

-toothed  poplar,  238 

Larkspur,  264,  268,  269 

Flower,  348 

-leafed   violet,  328 

Lasts,  Manufactured  from  birch 

wood,  247 

Lath,  Manufactured  from  white 

pine,  186 

Laurel,  264,  275,  350 

Lead  pencils,  Manufactured 

from  red  cedar,  193 

Lead-plant,  298, 301 

Leaf,    Fern,  161 

-green,  1 17,  429,  438,  488,  499 

Floating-fern,  Alga  in,  169 

-spot-fungus,  83 

-spot-fungus,  Number  in 

Minnesota,  84 

-succulent,  282, 473 

Leafless  habit  of  plants,  214 

Leaflessness,  Swamp  plants,  457 

Leafy  liverwort,  Allies,  141 

liverworts,  Capsule,  141 

Leatherleaf,  350,  356,  460 

Leather-leafed  wintergreen,  437 

Leatherwood,  332 

family,  332 

Poisonous   bark,  332 


546 


Minnesota  Plant  Life. 


Leaves,  423, 435 

Adaptation  for  spreading  to 

sun,  429 

Coatings,  465 

Desert  plants,  464 

Floating,  449 

Habit  of  shedding,  425 

Position  on  plant  body,  429 

Propagation,  512 

Rain  tips,  435 

Rolled   margins,  457 

Shapes,  430 

Sizes,  430 

Sleep-position,  427 

Submerged,  417, 449 

Water  plants,  450 

Fern,  What  they  really  are,     170 

Ledum  oil,  354 

Legume,  280 

Definition,  295 

Lemon,  305 

Lesser  wintergreen,  351 

Lettuce,  399 

Compass-plant,  464 

Lamb-,  393 

Prickly,  403 

Wild   (Engr.  403),      402,403,476 

Lichen  (Half-tone,  95),  22,  91,  424, 

438,  439,  459,  467,  470,  472,  489 
Age,  96 

and  algae,  93 

Comparison  with  higher 

plants,  98 

Economic  importance,  97 

Edible,  gg 

heath,  469 

Life  of,  QI 

Minnesota,  95 

Number  in  Minnesota,          27,  95 
parasites,  98 

partnerships,  98 

Propagative  bodies,  94 

Starch-making,  99 

Structure,  93 

Black-fungus,  98 

-fungus,  95, 5I8 

Limestone,  gi 

"Old  man's  beard"   (Half- 
tone), 93 
Reindeer  moss    (Half-tone, 

97),  96,  462,  469 

Rock  (Half-tone,  92),    93,  96,  467 
Sandstone,  9I 

Tamarack,  QI 


Licorice,  Wild,  298,  302 

Lid-moss,  149 

Life-history,   Cottonwood,  183 

Club-moss,  156 

Fish-mould,  46 

Liverwort,  124 

Mildew,  46 

Moss,  123,  124 

Stinking  smut  of  wheat,  49 

Life-period,  509 

Light,  Effect  on  plants,  428 

Influence  on  growth  of 

stems,  432 

-producing  bacteria,  102,  115 

Lilac,  360 

Lilac-blight,  80 

Lily,  224,  460,  471 

Allies,  225 

Flower,  346,  347,  348 

Calla,  217 

Easter,  224,  513,  524 

of  the  Amazon,  Giant,  433 

Pond-   (Half-tone,   12,  204), 

13,  266,  451 

Pond-,  Common  yellow,  448 

Sweet-scented,  266 

Tuber-bearing,  266 

Water-  (Half-tone,  265),  13, 

266,  273,  351,  448,  449 
Water-,  Leaves,  435 

Water-,  Small  while,  266 

Lime..  305 

encrusting  bass-weed,  38 

encrusting  blue-green  algae,       30 
encrusting  slime-mould,  28 

encrustation,  Algae   (Half- 
tone), 31,35 
oxalate  crystals,  217 
-secreting  algae,  41 
Limestone  formed  by  algae,  30 
lichens,                                             91 
pebbles  in  Lake  Micnigan,         41 
region  vegetation,                       463 
Linden,                                                 323 
Flower,                                         348 
American,                                      321 
Linen,                                                    306 
Linseed-oil,                                           306 
Lippia,                                                    373 
Live-forever,                                465,  474 
-oak,                                        428, 438 
Liverwort,    42,  122.  439,  460,  472, 

496,  513,  515,  519,  520,  521,  523 
Air  chambers,  135 


Minnesota  Plant  Life. 


547 


Liverwort,  Breeding  habits,  123 
capsule,  154 
capsule,  Origin  and  de- 
velopment, 130 
distinguished    from    moss, 

123,  126,  144 

Economic  importance,  143 
elaters,  135,  140 
First-stage,  124,  128 
Fruit,  123 
Life-history,  123,  124 
.Minnesota,  I32 
Number  in  Minnesota,  27 
Origin,  122 
Relation  to  disc-alga,  129 
Reproduction,  127 
Scientific  interest,  143 
Second-stage,  125,  126,  128 
Spores,  135 
Spore  distribution,  440 
Water-pocket,  142 
Cone-headed,  133,  518,  520 
Cone-headed,  Capsule,  134 
Cone-headed,  Spermary,  136 
Floating,  132 
Horned,  139 
Horned,  Capsule,  139 
Horned,  Relation  to  club- 
moss,  140 
Leafy,  141 
Leafy,  Capsule,  141 
Mud-flat  (Engr.  132),  132 
Purple-edged,  137 
Swimming,  133 
Umbrella-  (Engr.  136,  138),  137 
Umbrella-,  Propagative 

branches,  137 
Living   substance,  484,  508 
Chemical  composition,  487 
Growth,  492 
Irritability,  498 
Location,  485 
Physical  structure,  .  486 
Physiological  character,  488 
Requisitions  made  on  en- 
vironment, 488 
Lizard' s-tail,  236,  237 
-tail,  Resemblance  to  plan- 
tain, 237 
Lobelia,                                 388,  394,  397 
Flower,  394 
Resemblance  to  figwort,  397 
Resemblance  to  mint,  397 


Lobelia,  Blue  (Engr.),  396 

Blue,  Large,  397 

Blue,  Pale,  397 

Indian-tobacco,  398 

Kalm's,  398 

Red,  397 

Water,  396,  448,  449,  450 

Water,  Leaves,  417 

Loco-vetch,  302 

-weed,  302 

Locust,  280,  298,  301,  417,  427 

Honey-,  280 

Lombardy  poplar,  238,  240 

Long-headed  coneflower,  409 

-leafed  ground-cherry,.  378 

-leafed  Houstonia,  390 

-leafed  willow,  241,  242 

-spurred  violet,  329 

Loosestrife,  333,  358 

family,  332 

False,  334,  35« 

Purple,  334 

Swamp,  333, 334 

True,  333 

Tufted,  358 

Lopseed,  367,  386 

Low  birch,  246,  247 

blackberry,  291 

blueberry,  356,  357 

false  indigo,  301 

ground-cherry,  378 

serrated  wintergreen,  351 

snowberry,  392 

Lotus,  13, 300 

Indian,  264,  267,  452 

of  the  Nile,  267 

Louisiana  broom-rape,  386 

Lousewort  (Engr.  382),    379,  385,  438 

Parasitism,  383 

Lucerne,  298 

Lumpy-jaw,  107 

Lungwort,  371,  372 

Tall,  372 

Virginia,  372 

Lupine,  280,  298 

Wild   (Engr.),  298 

Lycopodium  powder,  156 

Lygodesmia,  404 

Lymph,   Koch's,  108 

Lythrum,  334 

Seed,  334 

Machinery,  Manufactured  from 

elm,  253 


548 

Machinery,  Manufactured 

from    sugar    maple,  3J6 

Manufactured  from  white  ash,  360 

Madder,  388,  525 

family,  388 

Magnetism,  Effect  on  plants,         437 

Magnolia,  264, 268 
Fossil, 

Maiden-hair  fern,  165 

Maize,  2°5 

Mallow,  32i,  323 

False,  323 

Glade-,  323,  325 

Poppy-,  323,  325 
Poppy-,  Triangular-leafed,        324 

Prairie,  325 

Rose-,  323,  325 

Rose-,  Halberd-leafed,  323,  325 

Round-leafed,  323 

Man,  21 
An  agent  in  plant  distribution,  21 

Mandrake  (Engr.),  275 

Wild,  274 

Mangrove,  332 

swamp,  442, 473 

Mankato,  297,  325 

Manomin,  207 

Many-flowered  prairie-clover,        300 

Maple    (Half-tone,   309), 

22,  252,  305,  309,  462,  475,  478 

Seed  distribution,  20 

Flower,  426 

trees,  313 

underbrush,  477 

woods,  6 

Maple,,  Ash-leaved,  313 

Bird's-eye,  316 

Black,  313,  316 

Curly,  315,  316 

Hard,  313 
leaf  tar-spots, 
-leafed   arrowwood, 
Moosewood  (Engr.  316),  313, 

Mountain-  313, 

Red,  313, 
Silver-leafed, 

Soft,                                313,  314, 
Sugar    (Engr.   314.    Half- 
tone, 315),  313, 

Marcgravia, 

Mare's-tail,  335, 

Marigold,  Beck's, 


78 
39i 
3i6 
317 
3i5 
238 
502 

315 
326 
450 
411 


Minnesota  Plant  Life. 

Marigold,  Bur-,  410 

Bur-,   Submerged   leaves.  417 

Bur-,  Water  (Engr.  414),  449 

Marsh-   (Eng.  268),  459 

Wrater-,  411 

Marine  algae,  39,  40 

Marsh  (Half-tone,  452),  453 

in  oak  wood  (Hall-tone),  250 

plants,  418 

Reed,  457 

Salt,  259 
vegetation  (Half-tone,  406),      451 

-bellflower,  396 
-elder,                                     402, 405 

fleawort,  412 

groundsel,  412 
marigold,                        264,  268,  459 

-marigold,   Floating,  268 

St.  John's-wort,  326 

-violet,  328 

Massive  dodder,  369 

Masts,  Ship,  Manufactured  from 

white  pine,  186 

Mats,  Indian,  Manufactured 

from  white  cedar,  190 

Mat-grass,  211 
plant,  24,  211,  418, 

429,  434,  470,  480 

spurge,  308 

Matches,   Manufactured  from 

white  pine,  186 

Matting,  Manufactured  from 
sedges, 
Manufactured  from  hemp, 

May-apple    (Engr.  275), 

Meadow  (Half-tone,  475), 
Moss, 


Wet, 

-parsnip, 

rose, 

-rue, 

salsify, 

-sweet, 

violet, 

Meat,  Diseases, 
Mechanical  forces, 

tissue, 
Melon, 

-cactus, 
Melostoma, 
Mendota, 
Menziesia, 
Mermaid-weed, 


216 

253 
274 
12,  475 
459 
459 
338 
291 

264,  268,  273 
403 

286,  459 
328 

H3 
420 
450 
394 

330,  465 
332 
267 

350,  354 
336 


Minnesota  Plant  Life. 


549 


Mesophyte, 
Mesophytic  shrub, 

vegetation, 
Microbe, 
Mignonette, 


442,  473 
477 
475 
101 

275 


Migrating   plants,    Struggles,  24 

Mildew,  46 

Life-history,  46 

Nutrition,  46 

Mildew,   Grape,  46 

Mustard,  46 

Potato,  46 

Shepherd's-purse,  46 

Milfoil,  13 
True,  336 
True,  Resemblance  to  pond- 
weed,  336 
Water,  448 

Milk-curdling  bacteria,  114 

Diseases,  112 

-fermenting  yeast,  74 

Fermented,  114 

-souring  bacteria,  113 

"Turnip  odor,"  113 

Milkweed  (Half-tone,  12,  366), 

7,  360,  364,  515 
Strengthening  device  for 

leaves,  423 

Flower,  365 

Insect  pollination,  364 
Resemblance  to  dogbane,         364 

Seed  distribution,  20 

Milkweed,  Blunt-leafed,  366 

Common,  366 

Florida,  367 

Four-leafed,  366 

Green,  367 

Green,  Broad-leafed,  367 

Green,  Woolly,  367 

Hairy,  366 

Oval-leafed,  366 

Poke,  366 

Purple,  365 

Showy,  366 

Sulliv  ant's,  366 

Swamp   (Engr.  365),  365 

Tall,  366 

True,  367 

Whorled,  366 

Milkwort,  307 

Mille  Lac,  259 

Millet,  205, 206 

grass,  Smut,  48 


Mimicry,  506 

Mimosa,  503 

Mineral  springs,  Bacteria,  120 

Minneapolis   (Twin  Cities),  221 

243,  267,  323,  325 

Minnehaha  falls,  281 

Minnesota  climate,  2 

geography,  i 

physical  history,  3 

Minnesota  river  (Half-tone),          235 

river  valley, 

7,  23,  262,  327,  330,  359,  387,  468 
Mint,  367,  375 

extracts,  378 

family,  375 

Flower,  377 

Pollination,  377 

Resemblance  to  figwort,  379 

Resemblance  to  lobelia,  397 

Horse-    (Half-tone,   376. 

Engr.),  377 

Mountain-,  377 

Water-,  377 

Wild  (Engr.),  375 

Mississippi,  river  (Half-tone,  14, 

410),  323,  327,  341,  362,  389 

Mistletoe,  233 

Parasitism,  439 

Miterwort,  283,  284 

Moccasin  flower,  228,  231 

flower,  Poisonous,  231 

flower,   Yellow,  231 

Moisture,  Adaptation  (Half-tone), 434 

Monkeyflower  (Engr.  381),     379,  381 

Moonseed,  264, 274 

Resemblance  to  wild  grape,  320 

Moonwort,  161 

Moor,  453 

Moosewood  maple,  313 

Morel  (Half-tone,  75),  72,  74 

Edible,  75 

Morning-glory,  367,  439,  478 

family,  367 

Moschatel,  388,  393 

Moss  (Half-tone,  12.    Engr.   125, 

127,   153),   12,  22,  42,   122,  424,  439, 

464,  467,  469,  470,  472,  476,  496, 
512,  513,  514,  519,  520,  521,  522,  525 

Breeding  habit,  123 

-capsule,  154 

-capsule,  Origin  and  develop- 
ment, 130 
Caterpillar  fungus,  82 


550 


Minnesota  Plant  Life. 


Moss,  distinguished  from 

liverwort,  123,  126,  144 

Deep  water,  453 

First-stage,  124,  128,  151 

Fruit,  123 

Gemma,  150 

heath,  468 

Life-history,  123,  124 

Minnesota   species,  144 

Number   in   Minnesota,  27 

Nutrition,  48 

Origin,  122 

Parasitic,  150 

Reproduction,  126,  127 

Second-stage,  125,  128,  151 

spermary  (Engr.),  126 

Spermatozoids,  126 

Spore  distribution,  153,  440 

stem,  152 

Terminal  type,  155 

Wet  meadow,  459 

Xerophytic,  472 

Moss,  Arbor-vitae,  152 

Bark,  149 

Carpet-,  152, 459 

Cigar  (Lichen),  97 

Cup-,  150 

Ditch,  203 

Dung-,  149 

Granite-,  148 

Hairy-capped,  151,  459,  472 

Higher,  148 

Lid-,  149 
Peat-   (Engr.    147.    Half-tone, 

212),  34,  145,  425,  459,  460,  462 

Peat-,  Fruit-body,  147 

Peat-,  Parasites,  45 

Peat-,  Spores,  49 
Peat-,  Warming-up  color.         146 

Pool-,  152 
River-,                   145,  151,  446,  448 

Rock,  467 

Rose-,  I5o 

"Spanish,"  91 

Tree-like,  IS2 

True,  I49 

Turf,  I50 

Water,  44g 

White,  I49 
Moss-plant  (Engr.  355,  Cassiope),  354 

Mould  parasite,  44 

Mould,   Black,  SI3 

Blue,  78,  86,  513 


Mould,   Fish-,  513,  515 

Fish-,   Life-history,  46 

Fish-,  Parasites,  45 

Green,  78 

Pill-throwing,  44 

Mountain-ash,  280,  286,  288,  290 

American,  289 

Western,  289 

Mountain  cranberry,  356 

holly,  312 

-honeysuckle,  392 

-maple,  313,  317 

-mint,  377 

Mousetail,  268,  272 

Flower  axis,  345 

Movement,  Growth,  500 

Protoplasmic,  498 

Mud-flat  liverwort,  132 

Mudwort,  371 

Mulberry,  251,  253 

Red,  253 

Mullein  (Half-tone,  380), 

367,  379,  430,  465,  476 

Mushroom  (Half-tone,  61,  62,  63, 

64)>                             61.  438,  513,  514 

Fruit-body,  63 

Gills,  513 

Prussic  acid  odor,  65 

Rules  for  eating,  61 

Spores,  Color,  65 

Mushroom,  Deliquescent,  63 

Edible,  61 

Milk,  64 

Miniature,  63 

Poisonous,  61, 82 

Mushroom,  True,   Characters,          62 

Classification,  65 

Musk  crowfoot,  388,  393 

Muskeg   spruce.  186,  192 

Mustard,  22.  275,  277,  512 

Mildew,  46 

Hedge-,  278 
Tumbling,   Seed  distribution,     21 

Myrrh,  340 

Myrtle,  332 

-leafed  willow,  240,  241,  460 

Naiad,  200.  450,  452 

Narrow-leafed  gentian,  363 

Labrador  tea,  353 

verbena,  374 

Nasturtium, 

305,  306,  432,  495,  497,  502,  525 

Neighbors,  Plant,  480 


Minnesota  Plant  Life. 


Nettle  (Half-tone,  254), 

234,  243,  251,  254 

Nettle,   Dead-,  375 

False,  254 

Hedge-,  375,  376 

Hemp-,  376 

-leafed  verbena,  374 

Slender,  254 

Stinging,  254 

Wood,  254, 255 

New  Jersey  tea,  319 

New  Ulm,  23,  262,  330,  332 

Nicollet  county,  297 

Nightshade,  367, 378 

family,  378 

Nightshade,  Black,  378 

Climbing,  379 

Cut-leafed,  378 

Deadly,  378 

Enchanter's,  335 

Prickly,  378 

Ninebark,  286 

Nitragin,  118 

Nitrogen   bacteria,  117 

salts,  103 

Nitrifying  bacteria,  102,  117 

Norway  pine  (See  red  pine),  188 

Nothocalais,  404 

Noxious  algae,  41 

Northwest  angle,    Inlet,  461 

Nucleus,  494 

Nutation,  500,  504 

Nutrition,  431,  439,  488,  489 

Bacteria,  102 

Bacteria,  Purple,   .  116 

Bladderwort,  384 

Butter  wort,  385 

Cow-wheat,  383 

Dodder,  368, 369 

Euglena,  445 

Fern,  48 

Flowering  plant,  48 

Fungi,  48, 87 

Higher  plants,  103,  118,  119 

Mildew,  46 

Moss,  48 

Pine-sap,  353 

Pitcher-plant,  278, 418 

Pond-scum,  33 

Purple  bacteria,  116 

Sundew,  280, 418 

Nuttall's  violet,  329 

Oak  (Half-tone,  245,  250.    Engr. 

249),  243,  249,  252,  428,  470,  475,  478 


Oak-barren, 

Gall, 

scrub, 

Seed   distribution, 
Oak,  Black, 

Bur, 

Chestnut, 

Chestnut,  Scrub, 

Live-, 

Poison-, 

Pore-fungus, 

Red, 

Root-fungus, 

Scarlet, 

White, 
Oats, 

Smut, 
Oblong-leafed  gentian, 


470,  478 
504 
477 

20 

249,250,251 

249,  251 

249,  251 

249,251 

428 

309,  310 

58 

249,  250 

89 

249,  250,  251 
249,  251 
205 
48 
362 


Odor,  Algae  with  pig-pen,  41 

Desert  plants,  465 

Mushroom  with  prussic  acid,     65 

Offset,  512 

Oil,  49l 

Ledum,  354 

Old  man's  beard  (Lichen),  91,  98 

Oleander,  435 

Olive,  360 

One-flowered  cancerroot,  386 

Wintergreen,  350 

Onion,                          450,  471,  491,  511 

Wild,  225 

Orange,  305 

Osage,  251 

Orchid 

(Half-tone,  n),  5,  146,  224,  228, 

438,  459,  46o,  463,  474,  515,  516,  525 

family,  474 

Flower,  347, 348 

Insect  pollination,  229 

Microscopic  female,  483 

Poisonous,  232 

Position  of,  349,  415 

Rein,  228,  231 

Root-fungus,  89 

Round-leafed,  229 

Tree-top,  428,  472,  481 

Tress,  228, 231 

Orchis,  Wild  (Engr.),  230 

Orders,  198 

Organs,  Irritability,  500 

Polarity  in,  501 

Organism,  Death  of,  484 

Origin,  Cell,  493 

Color  in  flowers,  426 


Minnesota  Plant  Life. 


Origin,  Club-moss,  123 

Fern,  123,   174 

Flowering  plant,  174 

Fungus,  88 

Gemma-propagation,  138 

Higher  plants,  129,  196 

Higher  plants,  Root,  157 

Higher  plants,  Seed,  160 

Life,  42 

Liverwort,  122 

Liverwort  Capsule,  130 

Moss,  122 

Moss  Capsule,  130 

Parasitism  in  plants,  439 

Pine,  123 

Orpine,  280 

family,  282 

Ortonville,  331 

Osage  orange,  251 

Osier,  Red,  341,  342 

Osmose,  495 

Ostrich-fern,  166 

Leaves,  173 

Oval-leafed  milkweed,  366 

Ovary,  197 

Higher  seed  plant,  Diagram 

(Engr.),  181 

Ovule,  Definition,  180,  184 

Oxeye,  409 

daisy,  407, 476 

Ox-yokes,    Manufactured    from 

elm,  253 
Paddles,  Indian,  Made  from  white 

cedar,  I90 
Painted-cup,  382 
Pale  blue  lobelia,  397 
dock,  258 
fumitory,  277 
Palm  of  Java,  Rotang,  39 
Sago,  I95 
Fossil,  26 
Panic-grass,  205 
Pansy,  42; 
Paper,  Manufactured  from  bass- 
wood,  ^2-\ 
Manufactured  from  white 

Poplar,  238 

birch,  246 

Pappus,  40Q 

Parachute,  Dandelion,  400 

Parasite,  4g9 

Definition,  44 

Parasite,    Cell-, 


Parasite,  Alga,  On  jack-in-the- 

pulpit,  37 

Algal  fungus,  45 

Bacteria,  453 

Desmid,  45 

Diatom,  45 

Dodder,  368, 439 

Fish-mould,  45 

Fungus,  49,  74,  98,  438,  506 

Land   plant,  46 

Lichen,  98 

Moss,  150 

Mould,  44 

Peat-moss,  45 

Pollen  grain,  45 

Pollen  grain,  Pine,  45 

Pond-scum,  45 

Root,  383 

Slime-mould,  27 

True  fungus,  48 

Parasitism,  Origin  of  in  plants,      439 

Dodder,  360) 

Eyebright,  383 

Lousewort,  383 

Yellow-rattle,  383 

Parnassia,  284,   363,   459 

Marsh  (Engr.)  283 

Parsley,  336, 459 

family,  338, 458 

family,    Poisonous    roots,          339 

family,  Umbels,  338 

Wild  (Half-tone,  339),  476 

Parsnip,  340 

Cow-,  338 

Meadow-,  338 

Water-,  338 

Wild,  338,  340 

Partnerships,   Plant,        89,93,94,117 

Plant,  Obtaining  food,  489 

Plant,   Intra-specific,  490 

Lichen,  98 

Partridgeberry  (Engr.  389), 

355,  388,  389,  424,  457 

Resemblance  to  cranberry,        389 

Resemblance  to  heath,  389 

Resemblance  to  twinflower,     391 

Pasque  flower,  268,  271,  426 

Passion-flower,  326 

Pasture   rose,  291 

Pawpaw,  264,  268 

Pea,  28o,  286,  417 

family,  295,  464,  500,  503 

Flower,  348 

Position  of,  349 


Minnesota  Plant  Life. 


553 


Pea,  Beach,  304 

Ground,  280 

Sensitive,  297 

Sweet,  295 

Peach,  280,  292 

Seed  distribution,  19 

Peach-leafed  willow,  241 

Peanut,  273, 280 

Wild,  297,  478 

Pear,  286, 290 

-blight,  103,  109 

Pearlwort,  263 

Peat-bog  (Half-tone,  11,  145),  12, 

34,  201,  213,  231,  279,  283,  354, 

355,  357,  381,  398,  442,  457,  459,  460 

-bog,  Formation,  146 

-bog,   Plants,  146 

-bog,  Raised,  146 

deposits,  26 

-moss,  22,  34,  145,  425,  459,  460,  462 

-moss,  Fruiting  habits,  147 

-moss,  Parasites,  45 

-moss,  Spores,  49 

-moss,  Warming-up  color,        146 

-moss,  Water-reservoir  cells,   145 

-tundra,  459, 461 

Pellitory,  254,  255 

Pembina,  259 

Pennyroyal,  375,  377 

False,  376 

Pennywort,  338 

Peony,  264 

Pepper,  236 

-grass,  275,  278 

Peppermint,  375,  377 

Peptone,  491 

Perching  fern,  472 

plant,  418, 439 

Perennials,  454, 462 

Peat-bog,  460 

Perfect  flower,  321 

Perfumery,  Mint,  378 

Perianth,  197,  346 

Persimmon  tree,  360 

Petunia,  367 

Phacelia,  371 

Philadelphia  ground-cherry,  378 

Phlox,  367,  369 

Blue,  369,  370 

Common,  370 

Downy,  369,  370 

Smooth,  369,  370 

Phosphorescence,  Bacterial,  104 

Pickerel-weed,  222 


Pieplant,   Wild,  413 

Pigeon  river,  353 

Pignut  hickory,  243,  244 

Pigweed,  259, 476 

Winged,  259 

Pilewort,  381 

Pill-throwing  mould,  44 

Pimpernel,  False,  379 

Scarlet,  359 

Pin-cherry,  293 

Pine,  7,  9,  22,  24,  185,  186,  196,  465, 

496,  502,  515,  516,  517,  52i,  524,  525 

Comparison  with  yew,  194 

cone,  Arrangement  of  scales,    346 

cone,  Prototype  of  the 

flower,  343 

Flower,  Pistillate,  186 

Flower,  Staminate,  186 

forest,  6,  342,  472 

Origin,  123 

pollen  grain  parasites,  45 

seed,  182 

seed  distribution,  20 

Jack  (Engr.  188),  186 

Jack,  Economic  importance,     190 
Norway,  188 

Pitch,  187 

Red,  186,  188,  472,  507 

Red,  Economic  importance,      188 
White  (Half-tone,  7,  187, 

189,  195),  186,  472,  507,  509 

White,  Economic  importance,  186 
White,  Resin,  187 

-drops,  350,  352,  438 

-knot  fungus"  54 

-sap,  350,  353,  438,  490 

-sap,  Nutrition,  353 

-sap,  Resemblance  to  In- 
dian-pipe, .    353 
Pineapple,  223 
Pink,                                 12,  259,  263,  468 
-flowered  wintergreen,  351 
Grass,  231 
Indian,  379 
Pinweed,                                      326, 327 
Pipe-vine,                             256,  257,  418 
-vine,  Insect  pollination,            257 
Pipestone  county,               330,  359,  468 
Pipe  wort,                               221,  420,  448 
Pipsissewa,                                   350,  352 
Pitch  pine,  187 
Pitcher-plant  (Engr.  278.    Half- 
tone, 461),          146,  278,  280,  459,  460 


554 


Minnesota  Plant  Life. 


Pitcher-plant,    Bacteria,  279 
-plant,  Nutrition,                 278,  418 
Plankton,  443 
Planktonic  flowering  plants,  445 
Plant,  Adaptations  against  cold,  425 
Adaptations,  Defensive,  506 
Adaptations  against  evapora- 
tion, 437 
Adaptations   against   illumi- 
nation, 433 
Adaptations,    Influences    af- 
fecting, 480 
Adaptations,  Intra-specifk,  440 
Adaptations   against  loss  of 

heat,  427 

Adaptations  to  moisture,  434 
Adaptations  for  reducing 

transpiration,  455 
Adaptations,  Seed  distribu- 
tion, 440 
Adaptations  to  surroundings,  417 
Adaptational  groups,  417,  442 
Animal  types  of  defense,  505 
Architectural  structure, 

179,  418,  424,  505 

armor,  506 
Branch  system,                    422,  423 

Climatic  history,  427 

Comparison  with  animals,  25 


Dangers,  exposed  to, 

diseases, 

distribution, 

Erect  habit, 

Food  (See  nutrition), 

Effect  of  light  on, 

Growth,  Hours  of, 


506 

IOQ 

5,  18,  21 
130 

488,  489 
428 
43i 


Growth,  Temperature  limit,      424 

individual,  Maintenance 

Lower  seed, 

Number  in  Minnesota, 

Origin  of  flowering, 

migrating,  Struggles, 

organs,    Elasticity, 

organs,  Irritability, 

organs,   Polanty, 

products, 

Introduced, 

Leaf-shedding  habit, 

Leafless  habit, 

in  Minnesota,  Number, 

in  the  world,  Number, 

Parasites  on  land, 

partnerships, 

Peat-bog, 


483 

194,  517 
27 
174 
24 
42  r 
500 
501 
491 
ii 
425 

214,  457 
26 
26 
46 

89,93,  H7 
146 


Plant  populations  in  a  state  of 
tension,  IQ 

Relation  to  other  living 

things,  438 

Root  system,  434,  435 

Seed-producing,  184 

Self  defense,  505 

species,  Maintenance,  509 

Stem,  8,  418 

Starch-making  of  green,  429 

Terrestrial,  Aquatic,  nature  of,  196 
Transpiration  of  water,  436 

Two-leaved  seedlings,  233 

zones,  10 

Air-,  472, 489 

Aquatic,  417,  418,  422,  434,  442, 

447,  450,  489 

Aquatic,  Reproduction,  451 

Aquatic,  Retraction  of  fruit,  452 
Bar,  447 

Bar,  Distribution,  451 

Bog,  436 

Braced-,  179 

Camphor,  326 

Carnivorous, 

278,  418,  438,  460,  481,  489 
Carpet,  211 

Cheese,  323 

Climbing,  439 

Indigo-,  280 

Desert,  418,  428, 

436,  442,  463,  481,  506 
Desert,  Leaves,  464 

Desert,  Odor,  437,  465 

Evergreen,  428 

Flowering,  490,  514,  518 

Green,  488 

Higher,  196,  490,  513,  523,  525 

Higher,  Comparison  of 

lichens  with,  98 

Higher,  Difference  between 

higher  animals  and,  128 

Higher,  Fecundated  egg,  128 
Higher,  Nutrition,  103,  118,  119 
Higher,  Origin,  129,  196 

Higher,  Origin  of  root,  157 

Higher,  Prostrate  stems,  131 

Humus,  479, 489 

Lead-,  298,  301 

Marsh,  418,  436 

Mat,  211,418,429,434,470,480 
Perching,  418 

Rain-water,  446 

Roadside,  10 


Minnesota  Plant  Life. 


555 


Plant.   Rock,      418,  446,  467,  468,  469 
Rosette,  429,  433,  47O 

Salt,  '  436,473 

Sand,  469.  470 

Sensitive,  280 

Sensitive,   Wild,  297 

Shade,  219, 418 

Shore,  447 

Shore,   Distribution,  451 

Sun,  418 

Surf,  214,  420 

Swimming,  445 

Switch,  214 

Tea,  326 

Twining,  439 

Wand,  418,  472 

Yeast,  73 

Plantain,        375,  386,  468,  470,  473,  480 
family,  4T5 

Flower,  387 

Resemblance  to  lizard's-tail,    237 
Bracted,  387 

Common,  387 

Heart-leafed,  387 

Indian,  412 

Rattlesnake,  231 

Rib,  387 

Rugel's  (Engr.  386),  387 

Salt  marsh,  387 

Water-,  197,  201 

Woolly,  387 

Plates,  506 

Plow-handles,   Manufactured 
from  hickory,  244 

Plum,  280,  292,  478 

Black  knot,  85 

Canada,  293 

Ground-.  298 

-pocket,  74 

Pocket-fungus,  74 

Wild,  293 

Pocket-fungus  on  cherry,  74 

-fungus  on  plum,  74 

-;ungus  on  poplar,  74 

Pogonia  (Half-tone,  n),  228 

Poison-ash,  310 

-dogwood,  310,  506 

-elder,  310,311,312 

-hemlock,  338,  339 

-ivy,  309,310,311,506 

-ivy.  Resemblance  to  wood- 
bine, 31.1 
-oak,                                        309,  310 
-sumac,                                   310,  462 


Poisoning,  Antidotes  for  ivy  or 

elder,  311 

Poisonous  algae,  41 

ergot-tuber,  82 

fungi,  Tamarack  swamp,  59 

leatherwood  bark,  332 

moccasin  flower,  231 

mushroom,  61,  82 

orchid,  232 

parsley   roots,  339 

pore-fungus,  82 

shelf-fungus,  59 

Poke  milkweed,  366 

Pokeweed  (Engr.  260),  259,  261 

Polemonium,  370 

Polishing  powder,    Diatom,  39 

Pollarded  willow,  241 

Pollen  grain,  Definition,  181,  184 

grain,    Parasites,  45 

spores,  517 

spores,  Germination  in  sugar,    502 

-tube,  Definition,  182 

Pollination,  345,  517 

Cross-,  230,517 

Insect,  348 

Bladderwort,  384 

Milkweed,  364 

Mint,  377 

Orchid,  229 

Pipe-vine,  257 

Polygala,  305,  307 

family,  307 

Polypody,  165,  468 

Pomegranate,  332 

Pomme  de  terre,  298,  300 

Pond-lily,  13,  30,  266,  451 

-lily,  Common  yellow,  266,  448 

-lily,  Small  yellow,  266 

-scum  (Engr.  34.    Half-tone, 

35),  33,  4i,  443 

-scum,  Nutrition,  33 

-scum,,  Parasites,  45 

-scum,  Reproduction,  33 

-scum,  Starch-construction,        33 

Pondweed  (Half-tone,  199),  13,  38, 
199,  273,  448,  450,  45i,  452,  453,  512 
Resemblance  to  true  milfoil,     336 
Clasping-leaved  (Engr.),          200 

Pool-moss,  152 

Poor  man's  weather-glass,       358,  359 

Poplar   (Half-tone,   195), 

233,  237,  238,  425-  427,  470,  478 
scrub,  477 

Seed  distribution,  20 


556 


Minnesota  Plant  Life. 


Poplar  vegetation  (Half-tone),      237 

Balsam-,  238, 239 

large-toothed,  238 

Lombardy,  238, 240 

pocket-fungus,  74 

Silver-leafed,  238 

White,  238 

Poppy,  275 

-mallow,  323,  325 

-mallow,  Triangular-leafed,      324 

Pore-fungus,  57 

Edible,  58 

Oak,  58 

Poisonous,  82 

Sulphur-colored,  58 

Willow,  58 

Portulaca,  259, 465 

Posts,  Manufactured  from  jack 

pine,  190 
Potato,                        367,  431,  491,  511 
-bug,  379 
-bug  plant,  379 
disease,  46 
Mildew,  46 
-scab,  103,  109 
Sweet,  227,  367 
Prairie  (Half-tone,  9),  471 
Dominant  plants,  7 
and  forest,  Difference  be- 
tween, 8,   14 
Minnesota,  6 
Prairie-clover,  297,  301 
Many-flowered,  300 
Purple,  301 
Silky,  301 
Silver-leafed,  300 
White,  •  301 
-dock,  409 
evening  primrose,  Shrubby,      335 
grass  (Half-tone,  471),  437 
mallow,  325 
rose,  291 
-turnip,  300 
violet,  328 
Preserves,  Silver  buffalo-berry,      333 
Prickle,  506 
Prickle-fungus,  56 
Prickly  ash,  305,307 
gooseberry,  284 
lettuce,  403 
nightshade,  378 
-pear,  319,  329,  465 
-pear  cactus,  23,  468 


Prickly-pear  cactus,  Western,  330 

Edible  fruit,  330 

Primrose,  357,  358,  426,  475 

Evening-, 

332,  334,  426,  429,  468,  470,  478 

Evening-,  Rootstock,  455 

Evening-,  Shrubby  prairie,  335 

Evening-,  White,  335 

Production  of  seed,  180 

of  eggs,  521 

of  spermatozoids,  519 

of  spores,  513 

Propagation,  511 

Origin  of  gemma-,  138 

Propagative  bodies  of  lichens,  94 
branches  of  Umbrella-liver- 
wort, 137 
bulbils  of  bass-weed,  38 

Prostrate  stems,  131 

Clover,  299 

Proteids,  491 

Protoplasm(Seelivingsubstance),  484 

Movement,  498 

Prussic  acid,  292 

Ptomaines,  107 

Puccoon,                                      371,  372 

Broad-leafed,  373 

European,  373 

Hoary,  372 

Yellow,  373 

Yellow,  Closed  flowers,  373 

Puff-ball,                                66,  67,  513 
Ball-tossing,                              70,  71 

Giant,  69 

Hard-skinned,  70 

Slitted,  69 

Stalked,  68 

Truffle,  67 

Tufted  (Half-tone),  69 

Warty  (Half-tone),  68 

Pulp,  Manufactured  from  box- 
elder,  317 
Manufactured   from  cotton- 
wood,  239 

Pulse   (Half-tone,   10),  471 
family,                                     280, 295 

Pulvinus,  503 

Pumpkin,  394, 395 

Fruit,  423 

Purple,  Bacteria,  116 

bacteria,  Nutrition,  116 

bacterial,  116 

cactus,  329 


Minnesota  Plant  Life. 


557 


Purple-edged  liverworts,  137 

loosestrife,  334 

milkweed,  365 

prairie-clover,  301 

Purslane, 

24,  259,  262,  437,  465,  468,  474,  476 

Rock,  474 

Salt-loving,  473 

Water-,  333 

"Pussy"  willow,  241 

Putrifaction  bacteria,  102,  109 

Putty-root,  228, 232 

Pyrola,  Root-fungus,  89 

Quarantine,  107 

Quartz  (See  silica),  32 

Quince,  280,  286,  290 

Quillwort    (Engr.    164), 

163,  448,  449,  450,  518,  519,  520 

Air  chambers,  163 

Leaves,  417 

Quinine,  388 

Radial  symmetry  of  flowers,  228 

Radish.  277 

Rafflesia,  256 

Ragweed  (Engr.  405), 

11,  399,  401,  405,  468 

family,  402 

Tall,  405 

Ragwort,  401, 412 

Railway  construction,  Red  pine 

used  in,  188 

Rain-water  plants,  446 

Rainy  lake,  190,  194,  327,  469 

river,  362 

Raised  peat-bog,  146 

Raspberry,  280,  290 

Seed  distribution,  19 

Arctic  dwarfed,  291 

Black,  291 

Creeping,  291 

Creeping,   Resemblance  to 

violet,  291 

Red,  291 

Sour.  291 

Rat  Portage,  Ontario,  Poplar  veg- 
etation near  (Half-tone),  237 
Rattlebox,                                   267, 298 
Rattlesnake  plantain,  231 
root  (Engr.  404),                  402,  404 
Ravine  vegetation  (Half-tone),     447 
Red  algae,                   29,  446,  513,  520 
algae,  Reproduction,  40 
ash,                                                361 


Red  bacteria,  115 

birch,  246,  247 

cedar,                     186,  192,  193,  472 

cedar,  Flower,  346 

clover,  298 

currant,  284 

elm,  252 

lake,  304 

-leafed  wintergreen,  351 

lobelia,  397 

maple,  313,  315 

mulberry,  253 

oak,  249, 250 

osier,  341, 342 

pine,                      186,  188,  472,  507 
pine,  Economic  importance,    188 

raspberry,  291 

river,  3 
river  valley,  7,  259,  260,  263., 

332,  333,  359,  376,  387,  473,  476 

rust,  51 

seaweed,  522,  523 

snow,  36, 424 

-stemmed  gentian,  363 

-veined  dock,  258 

-wood,   Fossil,  26 

Redbud,  280,  296 

Redroot,  259,  319 

American,  319 

pigweed,  261 

Red  Wing,  267 

Redwood  Falls,  193,  33° 

river,   Derivation  of  name,       342 

Reed  (Half-tone),  18,  199 

-grass,  13,  205,  206, 

451,  457-  458,  459 

-grass,  Rootstock,  455 

Marsh,  457 

Reed,  Bur-  (Engr.),  198 

Rein  orchid,  228,  231 

Reindeer-moss  (Lichen), 

96,  98,  141,  462,  469 

-moss,  Edible,  98 
Relations  of  bacteria  to  man,         120 

Reproduction,  488,  509,  512 

Definition,  511 

Black  mould,  44 

Fungus,  87 

Liverwort,  127 

Moss,  126,  127 

Pond-scum,  33 

Red  algae,  40 

Water-net,  36 


Minnesota  Plant  Life. 


Reproductive  cell, 

Resin, 

White  pine, 

Retting  bacteria, 

Rhododendron, 

Rhubarb, 

Ribs,  Canoe,  Indian,  Made  from 
white  cedar,  190 

-grass,  387 

plantain,  387 

Riccia,  Floating,  443 

Swimming,  443,  449 

Rice,   Wild    (Half-tone,   204,   208. 
Engr.  209),  205,  206,  207,  457 

River  birch,  246,  247 

K«ttle,  355, 357 

Minnesota  (Half-tone,  235), 
7,  23,  262,  327,  330,  359,  387,  468 
Mississippi,  14,  323,  327, 

341,   362,  389 

Pigeon,  353 

Rainy,  362 

Red,  3,  7,  259,  260, 
263,  332,  333,  359,  376,  387,  473,  476 
Redwood,  342 

St.  Croix  (Half-tone,  195),  56, 

179,  327,  330,  334,  355,  356,  389 
-moss,  145,  151,  448 

-moss,  Slime  covering,  447 

Riverside  grape,  321 

Riverweed  (Engr.  281),    280,  281,  446 
Pollination,  281 

Slime  covering,  447 

Roadside  plants,  10 

vegetation  (Half-tone,  10, 

254,  477), 
Rock  algae, 

cress,, 

-succulent, 

elm, 

-lichen, 

moss, 

plant, 

plant,  Air  chamber, 

plant,  Holdfast, 

purslane, 

-rose, 

-vegetation  (Half-tone, 

189,466), 
Rolling  alga, 
Root,  Fleshy, 

Higher  plants,  Origin, 

Poisonous, 

system, 


513       Root-hernia,  27 

187,  506  -parasites,  383 

187  nodules,   Clover,  117 

1 1 1  Ginseng,  337 

350  -cap,  Floating-fern,  220 

257,  504  -fungus,  80, 88,  481, 490 

-fungus,  Birch,  89 

-fungus,  Coral-root  orchid,  89 
-fungus,  Dutchman's  pipe,  89 
-fungus,  Oak,  89 

-fungus,  Orchid,  89 

-fungus,  Pyrola,  89 

-fungus,  Tamarack,  89 

-tubercle,  Bacteria,  119 

Rootstock,  455,  458,  512 

Rope,  Manufactured  from  hemp.  253 
Rose  (Half-tone,  291), 

280,  286,  291,  470,  478.  506 
Flower  axis,  345 

Fruit,  292,  294 

-mallow,  323, 325 

-mallow,  Halberd-leafed,  323,  325 
Meadow,  291 

-moss,  150 

Pasture,  291 

Prairie,  291 

Rock-,  326, 468 

Swamp,  291 

Wild,  Gall,  504 

Rosemary,  350,  355,  457,  460 

Resemblance  to  Kalmia,  354 

Rosette  plant,  429,  433,  470,  474 

Rosinweed,  401, 408 

Compass-plant   (Engr. 

411),  409,464 

476       Rotala,  333, 334 

467       Rough  alum-root,  283 

275, 278  -leafed  dogwood,  341 

468, 474      Round-leafed  dogwood,  341 

252  -leafed  June-berry,  287 

93, 96, 467  -leafed  mallow,  323 

467  -leafed  orchid,  229 

418, 467, 468, 469  -leafed  violet,  328 

446  -leafed  wintergreen,  350 

446       Royal  fern,  165 

262, 468, 474       Rue,  305 

326, 468  family,  307 

-anemone,  268,  269 

189  -anemone,  False,  268 

443  Meadow-,  268 

426  Meadow-,   Early   (Engr.),         272 

157       Rugel's  plantain,  387 

339       Rules  for  eating  mushrooms,  61 

434,  435       Runner,  512 


Minnesota  Plant  Life. 


559 


Rush  (Half-tone,  199,  224), 

224,  457,  458,  459,  460,  465,  470 

Bog,  225 

Wood,  225 

Russian  thistle,  260,  473,  474,  525 

thistle,  Seed  distribution,  21 

Rust,  48,  50 

Apple,  50 

Aster,  50 

Bean,  50 

Bellwort,  50 

Black  (Engr.  51),  51 

Blackberry,  54 

Flax,  50 

Goldenrod,  50 

Gooseberry,  54 

Horsemint,  50 

Juniper,  50 

Labrador  tea,  50 

Pear,  .       50 

Pine,  50 

Poplar,  50 

Red  (Engr.  51),  51 

Spruce,  50 

Sunflower,  50 

Tamarack,  50 

Thistle,  50 

Violet,  50 
Wheat  (Engr.  51,  52,  53),          50 

Willow,  50 

Rye,  205,  422 

Ergot,  81 

Wild,  470 

Sable  island  (Half-tone, 470),  253,  327 

Sac-fungus,  72,  74,  80,  95,  513 

Sage,  376 
-brush   (Half-tone,  408), 

402,  437,  464,  465 

Sago-palm,  195 

Salt-succulent,  474, 481 

marsh,  259 

marsh  plant,  436 

marsh   plantain,  387 

Nitrogen,  103 

plant,  473 

vegetation,  473 

Salvinia,  506,  515 

Counterpoise  area,  444,  445 

Sand-dune  (Half-tone,  470), 

211,  327,437 

plant,  469 

rock   (See  silica),  32 

vegetation,  469 

Sand-bar  willow,  241 

-binding  grass,  205,  211 


Sand-bar-binding  plant,  470 

-bur,  205,  210,  480 

-bur,  Smut,  48 

-cherry  (See  dwarfed  cherry),  293 

Sandalwood,  256 

Sandstone  lichen,  91 

Sandwort,  263 

"Sang,"  336 

Sanitation,  107 

Sarsaparilla,  Wild,  336,  337 

Sash,  Manufactured  from  white 

pine,  186 

Sassafras,  275 

Savin  (See  juniper),  186 

Saxifrage,  280,  283,  468 

Golden,  283 

Swamp,  283,  455,  459 

Scale,  506 

Pine  cone,  346 

-moss  (Liverwort,  142),       125,  126 

Scarlet  gaura,  335 

oak,  249,  250,  251 

pimpernel,  359 

Scheuchzeria,  457 

Scientific  interest  of  liverworts,      143 

Scouring-rush,     175,  439,  457,  476,  516 

-rush,  Deposit  of  silica,  175 

-rush,  Male  and  female 

plants,  178 

-rush,  Rootstock,  455 

-rush,  Minnesota  species,          178 

-rush  spores,  Germination,       177 

-rush,   Spores   (Engr.)  177 

-rush,  Stems,  176 

Screw-pine,  198 

Scrub   birch,  246 

chestnut  oak,  249,  251 

Sea-blite,  436, 473 

-milkwort,  358,  359 

Seaweed,  442, 453 

Edible,  41 

Fossil,  26 

Gigantic,  39 

Slime  covering,  447 

Brown,  520,  522,  523,  525 

Red,  522,  523 

Second-stage,  Liverwort,   125, 126,  128 

-stage,    Moss,  125,  128,  151 

Sedge  (Half-tone,  12,  18,  191,  224, 

458),  12,  13,  204,  212,  456, 

457,  458,  459,  460,  464,  465-  470 
Air-chamber,  455 

Characters,  216 

Economic  importance,  216 


56° 


Minnesota  Plant  Life. 


Sedge,  Flower  (Engr.),  210 

Manufacture  of  matting,  216 

Position  of,  349 

Resemblance  to  grass,  212 

Rootstock,  455 

umbel,  213 

Bulrush-   (Engr.)  214 

Carex-  (Engr.  215),  215 

Cyperus-  (Engr.  211),  213 

Smut,  48 

Seed,  Definition,  180,  184 

distinguished  trom  spore,          183 
Distribution,  18,  344,  416 

habit,  344 

Origin,  160, 440 

How  produced,  180 

Structure,  420 

-coat,  Definition,  182 

-plant,  184,  520,  522 

-plant,  Ancestors,  440 

-plant,  Breeding  habits,  181 

-plant,  Higher,  197,  517 

-plant,  Lower,  194,  197,  517 

-plant  and  primitive  seedless 

plants,  Relation  between,       195 
Cocoanut,  420 

Pine,  182 

Water-lily,  182 

wheat,  Smut  spores,  50 

Yew,  185 

Seedless  plants,  Relation  be- 
tween lower  seed-plants  and 
primitive,  195 

Seedlings,  233,  235 

Tree,  507 

Self  defense  of  plants,  505 

-preservation,    Instinct   of,        510 

Seneca  snakeroot,  307 

snakeroot,  Medicinal  value,      307 

Senecio,  412 

Senna,  280,  296,  297 

American,  297 

Sensitive  fern  (Half-tone,  432),        166 
pea,  297 

plant,  280,  427,  507 

plant,  Wild,  297 

Sequoia,  483 

Serrate-leafed  wintergreen,  351 

Serum  therapy,  108 

Shad-bush,  287 

Shade  plant  (Half-tone,  430, 
431,  432,  441),  219,  418 

Sheepberry,  390 

viburnum,  391 

Shelf-fungus,  57, 59 


Shelf-fungus,  Birch,  57,  58 

fungus,   Poisonous,  59 

fungus,  Toadstool-like,  59 

Shell-bark  hickory,  243,  244 

Shepherd's-purse,  275, 278 

purse,    Mildew,  46 

Sherburne   county,  327 

Shield-fern,  166 

Water-,  459 

Shingles,  Manufactured  from 

white  cedar,  190 

Manufactured  from  white 

pine,  186 

Shinleaf,  351 

Shoe-pegs,  Manufactured    from 

birch,  247 

Shooting-star,  358,  359 

Shore  plant,  447 

plant,  Distribution,  451 

Shoreweed,  387 

Showy  milkweed,  366 

Shrub,  428 

Dwarf,  428 

Mesophytic,  477 

Shrubby  heather,  469 

prairie   evening-primrose,         335 

Silica,  Deposited  by  algae,          32,  41 

Deposited  by   diatoms,  40 

Deposited  by  scouring-rush,     175 

Silk,   Corn,  207 

Silky  cornel,  34* 

dogwood,  428 

prairie-clover,  301 

Silver  buffalo-berry,  333 

-leafed  maple,  238 

-leafed  poplar,  238 

-leafed  prairie-clover,  300 

Silverberry,  332,  333,  465 

Sinter  formed  by  algae,  31 

Skin-fungus,  55 

Skull-cap,  375, 376 

Skunk-cabbage  (Half-tone,  218), 

197,  217,  218,  219 

-cabbage,  Warming-up  color,    218 

currant,  284 

Slender   nettle,  254 

Slime-mould,    26,  27,  438,  485,  493,  499 

-mould,  foam  patches,  28 

-mould,  Lime-encrusting,  28 

-mould,  Number  in  Minnesota,  27 

-mould  parasites,  27 

•    -mould,  Plants  or  animals,          27 

-mould,  Roots  of  cabbage,         27 

-mould,  Roots  of  turnip,  27 


Minnesota  Plant  Life. 

Slime-mould  spores,  28 

Slippery  elm,  252 

Slitted  puff-ball,  69 

Small  burdock,  413 

cranberry,  356,  357 

yellow  pond-lily,  266 

Smaller   duckweed,  220 

Smallpox  bacteria,  106 

Smartweed  (Half-tone,  12), 

257,  258,  456 

dodder,  369 

Water-,  258, 448 

Smilax,  197,  226,  439,  503 

Smooth  honeysuckle,  392 

-leafed  dogwood,  428 

phlox,  369,  3/0 

yellow  violet,  329 

Smut,  48, 49 

Sandbur,  48 

Corn  cockle,  48 

Indian  corn,  48 

Millet  grass,  48 

Oat,  48 

Peat-moss,  49 

Sedge,  48 

Wheat,  48 

Wheat,  Seed,  50 

Snakeroot,  307 

Distribution   of  fruit,  339 

Black,  338 

Button,  338 

Seneca,  307 

Seneca,  Medicinal  value,  307 

Snapdragon,                         367,  379,  381 

Sneezeweed,  401 

Snow-on-the-mountain,  308 

plant,  442 

vegetation,  453 

Snowberry   (Engr.   392), 

350,  357,  388,  391,  39^,  460 

Dwarf,  428 

Low,  392 

Soapwort,  263 

gentian,  363 

Soft  maple  (Half-tone,  452), 

313,  314,  502 

Soil,  Relation  of  to  plants,  437 

Sorrel,  258, 475 

True,  257 

Wood-,  305 

Wood-,  Violet,  306 

Wood-,  White,  306 

Wood-,  Yellow,  306 

Sour  raspberry,  291 

37 


561 


399,  402,  403 

91,  223,  438,  472 

217 

210 
509 

379,  382,  475 
5U,  520 
520 


Sow-thistle, 

"Spanish  moss," 

Spathe, 

Spear-grass, 

Species,  definition  of, 

Speedwell, 

Sperm, 

Spermary, 

Cone-headed  liverwort,  136 

Spermatozoids,  505,  512,  520 

Directed  toward  eggs,  499 

Distribution,  520 

Production,  519 

Bass-weed,  38 

Fish-mould,  46 

Moss,  126 

Red    algae,  40 

Sphere-alga,  37 

Sphere-alga,  37,  443,  520,  521 

Spice,  236 

-bush,  275 

Spider-flower,  275 

Spiderwort,  222 

Spikelet,  Grass,  204 

Spikenard,  336, 337 

Spindle  tree,  312 

Spine,  506 

Spiraea,  280,  286,  459 

Willow-leafed,  286 

Spleenwort,  165 

"Spontaneous   combustion,"  115 

Spools,  Manufactured  from 

birch,  247 
Spore,                                            512,  513 

distinguished  from  seed,  183 
distribution,  344,  514 
distribution,  Carrion-fungus,  66 

distribution,    Earth-star,  69 

distribution,   Morel,  75 

distribution,  Moss,  153 
Germination,  177,  518 

-mother-cell,  513 

Pollen,  517 

production,  513 

Beetle-fungus,  100 

Black  mould,  44 

Club-moss.  159 

Cup-fungus,  77 

Fly-cholera  fungus,  45 

Liverwort,  135 

Mushroom,  Color,  65 

Peat-moss,  49 

Puff-ball,  68 

Puff-ball,    Ball-tossing.  71 

Scouring-rush,  177 


562 


Minnesota  Plant  Life. 


Spore,   Slime-mould,  28 

Smut,  49 

Sphere-alga,  37 

Yeast-plant,  73 

Spore-producing  leaves,  Four- 
leaved  water-fern,  166 
Sporeling,    Care    of,                          519 
Spotted-leafed  geranium,                 305 
wintergreen  (See  Pipsisse- 

wa,  350,  352 

Spring-beauty  (Engr.  262),     262,  465 

flowers,  426,  479 

Spruce  (Half-tone,  7,  n,  145),  7, 

12,  24,  54,  192,  424,  436,  442,  457,  460 

Branch,  422 

Seed  distribution,  20 

swamp,  353, 472 

woods,  352 

Black,  186,  192 

Muskeg,  186,  192 

White,  186,  192 

Spurge,  305, 307 

family,  305,  418,  470,480,  506 

Seed  distribution,  20 

Flowering,  Resemblance 

to  dogbane,  308 

Mat,  308 

Spurred  gentian,  363 

Squash,  394 

Fruit,  423 

Squaw  huckleberry,  356 

-weed,  412 

Squawroot,  385 

Squirrel   corn,  276 

St.  Croix  river  (Half-tone,  195),  327 

St.  Croix  river  valley, 

56,  179,  330,  334,  355,  356,  389 

St.  John's-wort,  326 

Marsh,  326 

St.  Louis  county,  146 

St.  Paul,  221,  267,  323,  325 

St.  Vincent,  259 

Staghorn-fungus,  86 

Stalk-fungus,  95 

Stalked  puff-ball,  68 

Stamens,  197 

Definition,  181,  184 

Staminate  flower,  Pine,  186 

Star-cucumber,  394, 395 

-grass,  227 

Starch,  490 

-making,  Fungus,  48 

-making,   Green  plants,  429 

-making,  Lichens,  99 


Starch-making,  Pond-scum,  33 
Starflower,  358 
Starwort,  448 
Water-,  305,  308 
State  flower,  231 
Stearns  county,  341 
Stem,  426 
Annual  rings,  197 
Growth  of,  432 
-succulent,  474 
Methods  of  developing,  8 
Trailing,  512 
Bulrush,  422 
Higher  seed  plant,  234 
Moss,  152 
Water  plant,  450 
Xerophyte,  465 
Stickseed,  371,  372 
Stiff  gentian,  362 
water-buttercup,  272 
yellow  flax,  306 
Stigma,  517 
Definition,  181,  184 
Stinging  nettle,  254 
Stinking  smut  of  wheat,  48,  49 
Stitchwort,  263 
Stolon,  512 
Stone-crop,  282 
-crop,  Ditch,  282 
Stonewort,  38 
Storage  of  food,  490 
Strawberry,               280,  289,  419,   511 
Flower  axis,  345 
Stream-side   vegetation    (Half- 
tone), 227,448 
Struggles  of  migrating  plants,         24 
Strychnine  plant,  360 
Submerged  leaves,  449 
Substances  formed  by  bacteria,        103 
harmful  to  bacteria,  104 
Substratum,  480 
Relation  of  plant  to,  437 
Succulent,  473 
Origin,  474 
Sucker,  512 
Sucking  organ,  Dodder,  369 
Sugar,  316 
Manufactured  from  sugar- 
maple,  314 
-cane,  205 
-maple,  313,  315 
Sullivant's  honeysuckle,  392 
milkweed,  366 
Sullivantia,  283 


Minnesota  Plant  Life. 


563 


Sulphur,  102 

bacteria,                         102,  120,  453 

-colored  pore-fungus,  58 

Sumac  (Half-tone,  309),    309,  310,  475 

underbrush,  477 

Fragrant,  310 

Poison-  (Engr.  310),  310,462 

Summer  grape,  321 

Sun  plant  (Half-tone,  429),  418 

Sundew  (Engr.  280),  279,  460 

Nutrition,  280,  418 

Sunflower  (Half-tone,  9,  408), 

9,  399,  401,  402,  416,  470,  471,  490 

family,  394, 402 

Flower,  394, 409 

Head,  416 

herbs,  409 

Position,  413, 415 

Relatives,  405 

Seed  distribution,  21 

Sunflower  dodder,  368 

Surf  plant,  214,  420 

Surgery,  Antiseptic,  114 

Swamp  plant.  Air  chamber,  455 

plant,  Leaflessness,  457 

plant,  Tissues,  455 

underbrush,  462 

vegetation,  453,  455 

blackberry,  291 

blueberry,  457 

butterweed.  458 

cypress.  Knees,  438 

-dock,  258, 458 

hickory,  243,  244 

-honeysuckle.  392,  393 

loosestrife,  333,  334 

Mangrove,  442, 473 

milkweed.  365 

rose,  291 
-saxifrage  (Half-tone,  456), 

283,  455,  459 

Spruce,  353, 472 
Tamarack,             34.  145,  200, 

213,   221,   222,   231,    279,   283, 

318,  342,  357,  472 

valerian,  393,  394 

Sweet  cicely,  338 

cicely,   Fruit  distribution.         339 
clover,  298 

fern.  243,  460 

-flag,  217,  219,  437.  457,  458 

-flag,  Rootstock,  455 

pea,  295 

-scented  lily.  266 


Sweet  potato, 

violet, 

william,  Wild, 
Swimming  plants, 

liverwort, 

Riccia, 
Switch-plant, 
Sycamore, 
Tag-alder, 
Tall  bellflower, 

bilberry, 

blueberry, 

lungwort, 

milkweed, 

ragweed, 


227,  367 
328 

369,  370 
445 
133 

443,  449 
214 

280,  285 

246,  460 
396 
356 
356 
372 
366 
405 


Tamarack  (Half-tone,  n,  145, 
455),  12,  186 

191,  3io,  352,  436,  442,  457,  460 
swamp  (Half-tone,  191),  34, 

145,    20O,    213,    221,    222,    231, 

279,  283,  318,  342,  357,  472 

swamp,  Poisonous  fungi  of,      59 

cup-fungus,  78 

lichens,  81 

root-fungus,  89 

Tamarind,  280 

Tamarisk,  326 

Tan-bark,  250 

Tannin,  191,  506 

Tanning,  191 

bacteria,  in 

Tansy,  401, 411 

Tassel,  Corn,  207 

Tapioca,  305 

Tar  spot,   Maple  leaf,  78 

Taylor's   Falls    (Half-tone,    187, 

195),                                 262,  330,  353 

Tea,  Labrador,  456,  460 

plant,  326 

Tear-thumb,  258, 439 

Teazel  family,  388 

Fuller's-,  388 

Telegraph  plant,  500,  503 

poles,     Manufactured     from 

tamarack,  191 
poles,     Manutactured     from 

white  pine,  186 
Temperature  limit  of  plant 

growth,  424 

Tendril,  503,  504 

Tension,  Continental,  14 

Minor   (Half-tone,   14),  14 

Plant  populations  in  a 

state  of,  10 


564 


Minnesota  Plant  Life. 


Terrestrial  plants,  Aquatic 

nature,  196 

Thin-leafed  bilberry,  356 

Thistle,     11,  399,  401,  402,  413,  475,  476 

Position  of,  413,  415 

Russian,  260,  473,  474,  525 

Russian,  Seed  distribution,          21 

Sow-,  402,  403 

Thorn,  506 

Thoroughwort   (Half-tone,   406. 

Engr.  407;,  401,  402, 

406,  415,  462,  476 

Three-cornered  duckweed,      220,  444 

-leaved   ash,  307 

-leaved   elm,  307 

-pronged  duckweed,  133 

Thunder  Bay,  Lake  Superior,        322 

Tick-trefoil  (Engr.  303),          298,  302 

-trefoil,  Seed  distribution,  19 

Tickseed,  401, 410 

Ties,  Railway,  Manufactured  from 

tamarack,  191 

Railway,  Manufactured  from 

white  cedar,  190 

Tiger-lily,  225,  226,  512 

Timber,  250 

Timothy,  205,  206 

Tissues,  455, 496 

Bast,  497 

Cork,  497 

Mechanical,  450 

Milk,  497 

Pith,  496 

Reservoir,  496 

Skeleton,  497,  504 

Skin,  496 

Strengthening,  504 

Wood,  496 

Toad-flax,  256,  379,  380,  438 

-flax,  Canada,  381 

-flax,  Common,  380 

Toadstool,  61 

Edible,  61 

-blight,  80 

-like   shelf-fungus,  59 

Tobacco,  367 

-curing,  Bacteria,  in 

family,  378 

-root>  393, 394 

Indian,  407 

Wild,  379 

Tomato,  367 

hairs,  485 

Ground-,  378 


Tool   handles.    Manufactured 

from  elm,  253 

handles,  Manufactured  from 

sugar-maple,  316 

handles,  Manufactured  from 

white   ash,  360 

Touch-me-not  (Engr.  317.    Half- 
tone, 447),      305,  309,  318,  462,  479 
Seed  distribution,  19 

Town,  Duluth,  189,  259, 

262,  266,  284,  332,  354,  355,  357 
Fergus   Falls,  284 

Grand  Marais,  329 

Grand   Portage,  354 

Grand  Rapids,  145,  212 

La  Crosse,  267 

Lucerne,  298 

Mankato,  297,  325 

Minneapolis,  221,243,267,323,325 
New  Ulm,  23,  262,  330,  332 

Ortonville,  331 

Pembina,  259 

Rat  Portage  (Half-tone),         237 
Red  Wing,  267 

Redwood  Falls,  193,  330 

St.    Paul,  221,  267,  323,  325 

St.   Vincent,  259 

Taylor's     Falls     (Half-tone, 

187,  195),  262,  330,  353 

Trailing  arbutus,  350,  355 

Travertine  formed  by  algae,  31 

Tree  fern,  164 

-like  moss,  152 

-top  orchid,  428,  472,  481 

-top-succulent,  474 

Trees,  428 

Alliance  between  ants  and,      507 

Bark,  234 

Cambium,  234 

and  herbs,  Comparison  of,       234 

Dominant  forest  plants,  7 

Wood,  234 

Christmas  (See  spruce),  192 

Tress  orchid,  228,  231 

Trestles,  Manufactured  from 

red  pine,  188 

Triangular-leafed  poppy-mallow,    324 

Trillium,  225, 479 

Flower.  348 

Leaves,  430 

Tropical    vegetation,  424,  428 

True  fern,  163 

fungi,  43,  48 

ginseng,  337 


Minnesota  Plant  Life. 

565 

True  loosestrife, 

333 

Valsa, 

86 

milfoil, 

336 

Vegetable,   Diseases, 

113 

milfoil,  Resemblance  10 

Vegetation,  Abyssal, 

453 

pondweed, 

336 

Aquatic, 

450,  453 

milkweed. 

367 

Arctic, 

424,  428 

moss, 

149 

Climatic    formation, 

481 

mushroom, 

62 

Granitic   region, 

463 

primrose, 

35B 

Halophytic, 

473 

Solomon's  seal, 

225,  226 

Hot  spring, 

453 

sorrel, 

257 

Hydrophytic, 

462 

Truffle, 

72,78 

Limestone  region, 

463 

puff-ball, 

67 

Marsh, 

451 

Trumpet-creeper, 

418 

Mesophytic, 

475 

Tuber, 

426,  512 

Neighborhood, 

481 

-bearing  lily, 

266 

Roadside, 

476 

Ergot, 

82 

Rosette, 

474 

Tufted   loosestrife, 

358 

Salt, 

473 

Tulip,  Flower, 

348 

Sand, 

469 

tree, 

268 

Snow, 

453 

tree,  Fossil, 

26 

Substratum  formation, 

481 

Tumbleweed,                       259. 

260,  471 

Swamp, 

453,  455 

Tumbling  grass,                 205, 

2O6,  211 

Tropical, 

424,  428 

grass,  Seed  distribution, 

21 

Xerophytic, 

442,  463 

mustard,  Seed  distribution,        21 

Velvetleaf, 

323,  325 

Tundra, 

453 

Venus'  fly-trap,                   278, 

503,  505 

Peat-, 

459,  461 

looking-glass, 

396,  397 

Turf-moss, 

150 

Veratrine,    Alkaloid, 

226 

Turgor, 

494 

Verbena,        360,  367,  373,  468, 

475,  480 

Turnip, 

2/7 

family, 

373 

odor  of  milk, 

113 

Resemblance   to   borage, 

374 

Prairie, 

300 

Blue  (Engr.;, 

373 

Slime-mould, 

27 

Blue,  Wild, 

374 

Turpentine, 

187 

European, 

374 

Turtle-head, 

379,  38i 

Hoary, 

374 

Twig-fungus, 

85 

Narrow-leafed, 

374 

Twin-Cities, 

323 

Nettle-leafed, 

374 

Twinflower, 

388,  391 

Vetch,                                      7, 

297,  304 

Resemblance    to    partridge- 

Bacterial  nodules, 

118 

berry, 

391 

Loco-, 

302 

Twining  fern, 

164 

Viburnum, 

390 

Typhus  bacteria, 

1  06 

Sheepberry, 

391 

Umbel, 

337 

Vine  (Half-tone,  254), 

319 

Parsley    family, 

338 

Vinegar  bacteria, 

114 

Sedge, 

213 

fermentation,   Bacteria, 

102 

Umbrella-liverwort, 

137,  512 

Violet,                                   328, 

426,  462 

Umbrellawort, 

261 

Flower, 

348 

Underbrush  (Half-tone), 

478 

Position, 

349 

Swamp, 

462 

Resemblance  to  creeping 

rasp- 

Urine,    Bacteria, 

119 

berry, 

291 

Vaccination, 

107 

Arrow-leafed, 

328 

Valerian, 

388,  393 

Bird's-foot, 

328 

(drug), 

393 

Canada, 

329 

family, 

388 

Dog's-tooth, 

225,  226 

Greek, 

369 

Halberd-leafed. 

329 

Swamp, 

393,  394 

Kidney-leafed, 

329 

566 


Minnesota  Plant  Life. 


Violet,   Labrador,  329 

Lance-leafed,  329 

Larkspur-leafed,  328 

Long-spurred,  329 

Marsh-,  328 

Meadow,  328 

Nuttall's,  329 

Prairie,  328 

Round-leafed,  328 

Sweet,  328 

Sweet  white  (Engr.),  328 

wood-sorrel,  306 

Yellow,  Common,  329 

Yellow,  Smooth,  329 

Virginia  creeper  (Half-tone, 
322,  433),  319,  321,  336 

ground-cherry,  378 

lungwort,  372 

waterleaf,  370 

Volvox,  35 

Wagon-tongues,  Manufactured 

from  hickory,  244 

Wahoo,  309,  312 

Wakerobin,  225 

Walking- fern,,  165,  512 

Walnut,  243 

Seed  distribution,  20 

Black,  243, 244 

Wand  plants, 

303,  397,  404,  406,  418,  470,  472,  478 
Warm  water  algae,  42 

Warming-up  color,    265,  425,  426,  432 
color,  Arum,  218 

color,  Peat-moss,  146 

color,  Skunk-cabbage,  218 

Waste  products.,  Bacteria,  103 

Water  current,  21 

plants,  Ripening  of  seeds,         272 
plants,  Zonal  distribution,  12 

-reservoir  cells,   Peat-moss,       145 
Transpiration,  436 

-beech,  246 

bur-marigold,  449 

-buttercup,  272, 448 

-buttercup,  Fruit,  272 

-buttercup,  Submerged  leaves,  417 
cress,  275, 278 

crowfoot,  Submerged  leaves,    417 
-dock,  258 

eel-grass,,  449,  450 

eel-grass,  Holdfast,  447 

-fennel,  308 

-fern,  161,  444,  506, 

515,  5i6,  519,  520 


Water-fern,  Four-leaved, 

164,   1 66,   173,  448,  518 
-fern,  Four-leaved,  Spore-pro- 
ducing leaves,  166 
-flower,                         29,  30,  41,  443 
-flower,  Formation  of  gas 

bubbles,  29 

-hemlock,  338 

-hemp,  259, 261 

-hoarhound,  377 

-horse-tail,  178 

-hyacinth  (See  pickerel-weed),  222 
-hyacinth,  Counterpoise  area,  444 
-lily,  13,  264,  266,  273,  448,  449,  451 
-lily  family,  264 

-lily,  Leaves,  435 

-lily,   Seed,  267 

-lily,  Small  white,  266 

-lobelia,  396,  448,  449,  450 

-lobelia.  Leaves,  417 

-marigold,  411 

-milfoil,  332,  335,  448,  450,  452 
-milfoil,  Resemblance  to  blad- 

derwort,  384 

-mint,  377 

-moss,  448 

-net,  36 

plant,  418, 447 

plant,  Annual,  450 

plant,  Attached,  446 

plant,  Leaves,  450 

plant,  Perennial,  450 

plant,  Propagation,  451 

plant,  Retraction  of  fruit.  452 

plant,  Stems,  450 

-pocket,  Liverwort,  142 

-parsnip   (Engr.  338),  338 

-pimpernel,  358 

-plantain,  197,  201 

-purslane,  333 

-shield  (Engr.  264), 

13,  264,  433,  449 

-silk,  512,  520 

-smartweed,  258,,  448 

star-grass,  217,  222 

-starwort,  305,  308,  450,  451 

Waterleaf,  367,  370 

Appendaged,  370 

Virginia  (Engr.  370),  370 

Watermelon,  395 

Waterweed,  203,  450,  451,  453 

Wedge-leafed  cherry,  293 

Weeds  (Half-tone,  479),  n,  476 

Loco-,  302 


Minnesota  Plant  Life. 


567 


Weed,    Pickerel-,  222 
Western  blite,  260  ' 
mountain-ash,  289 
prickly-pear,   Edible  fruit,         330 
sand-cherry,  293 
Wet  meadow,  459 
Wheat,  22,  205,  209 
Cow-,  379,  383 
-rust,  50,  53 
rust  on  barberry,  50 
rust  on  borage,  50 
rust  on  buckthorn,  50 
Smut  of,  48,  50 
Smut,  Stinking,  48 
White  ash,  360 
cedar,  186,  190 
clover,  298 
Earth   Reservation,  362 
elm,  252 
evening-primrose,  335 
false  indigo,  298 
hickory,  243 
moss,  149 
oak,  249,  25 1 
pine,                    8,  186,  472,  507,  509 
pine  timber,   Economic  im- 
portance, 186 
poplar,  238 
prairie-clover,  301 
spruce,  186,  192 
water-buttercup,  272 
water-lily,   Small,  266 
wood-sorrel,  306 
White  Bear  lake,  267 
Whitewood,  268,  321 
Whitlow-grass,  275,  278 
"Whorled  milkweed,  366 
Wickerware,  Manufactured  from 

willow,  241 

Wild  bean,  297,  304,  478 

black  currant,  284 

blue  flax,  306 

blue    verbena,  374 

crab-apple,  286 

cucumber,  394,  396,  439 

elder,  336 

elder,  Resemblance  to  elder 

bush,  337 

ginger,  256,  257 

grape,  320,  418,  479 
grape.  Resemblance  to 

moonseed,  320 

lettuce,  402,  403,  476 

licorice,  298,  302 


Wild  mandrake, 
morning-glory, 
onion, 
parsley, 
parsnip, 
peanut, 
pieplant, 
plum, 


274 
467 

225,  226 
476 

338,340 

297,  304,  478 

413 

293 


rice,  13,  205,  206,  207,  457 

rice,   Ergot,  8/ 

rice,    Seed   distribution,  19 

rose,   Gall,  504 

sarsaparilla,  336,  337 

sensitive-plant,  297 

sweet  william,  369,  370 

tobacco,  379 

rye,  470 

water-fern,  444 

Willow   (Engr.  240.     Half-tone, 
14,  201,  421),  12,  22,  233,  237,  240, 

425,  427,  428,  459,  462,  472,  511 
Position  of,  349 

Gall,  504 

bark,  242 

Black   (Half-tone,  241),  241 

-blight,  80 

Bog-  (Half-tone),  n 

Bushed,  241 

Dwarf,  428 

Gray,  241 

Heart-leafed,  241, 242 

-herb,  7,  334,  459,  478 

-herb,   Flower,  347 

-herb,    Seed   distribution,  20 

Hoary,  241,  242 

-leafed  spiraea,  286 

Long-leafed   (Half-tone, 

241),  241,242 

Myrtle-leafed,  240, 241 

Peach-leafed  (Half-tone,  239),   241 
Pollarded,  241 

Pore-fungus,  58 

Pussy,  241 

Sand-bar,  241 

Shining-leafed,  242 

Wind  currents,  20 

Wine,   Souring  of,  114 

Winged  distribution,    Com- 
posites, 416 
pigweed,  259 
Winona  county,                          356,  393 
Wintergreen  (Engr.  351), 

22,  342,  350,  355,  472,  479 
bog,  351 


568 

Wintergreen,  Green-flowered,        351 

Leather-leafed,  437 

Lesser,  351 

Low  serrated,  35 1 

One-flowered,  35° 

Pink-flowered,  35 1 

Red-leafed,  351 

Round-leafed,  35° 

Serrate-leafed,  35  i 

Spotted,  352 

Witch-hazel,  274,  280,  284 

-hazel  extract,  285 

Witch's-broom,  54.  361,  504 

-broom,  Alder,  74 

-broom,    Cherry,  74 

Withe-rod,  321 

Wright  county,  327 

Wolfberry,  3Q2 

Wood  of  trees,  234 

Wood-pulp,  Manufactured  from 

basswood.  323 
-pulp,  Manufactured  from 

poplar,  238 

-bellflower,  396 

Wood-lily  (Half-tone),  430 

-nettle,  254, 255 

-rush,  225 

-sage,  375 

-sorrel,  305,  503 

-sorrel,  Violet,  306 

-sorrel,  White,  306 

-sorrel,  Yellow,  306 

Woodbine,  321, 432 

Resemblance  to  poison-ivy,      311 

Woodenware,  Manufactured  from 

basswood,  323 
Manufactured      from  box- 
elder,  317 
Manufactured     from  buck- 
eye, 318 
Manufactured       from  soft 

maple,  315 

Manufactured      from  white 

pine,  1 86 

Woodsia,  166 


Minnesota  Plant  Life. 

Woolly  green  milkweed,  367 

plantain,  387 

Worms,  20 
Wormwood  (Half-tone,  408;, 

402,411,437,464,465 

Xerophyte,  442, 463 

Xerophytic  moss,  472 

plant,    Stem,  465 

Yam,  224, 227 

Yarrow,  401,411 

Yeast,  72,  73 

Bread-making,  72 

Brewing,  72 

Cooked   cabbage,  74 

Fermentation  of  wine,  72 

Milk-fermenting,  74 

Hardening  of  cider,  72 

Manufactured  from  hops,  253 

Yellow  birch,  246,  247 

clover,  298 

dock,    .  258 

-eyed  grass,  221,  457 

flax,    Grooved,  306 

flax,    Stiff,  306 

fumitory,  277 

gentian,  363 

honeysuckle,  392 

moccasin,  231 

pond-lily,  Common,  448 

puccoon,  377 

-rattle,  379 

-rattle,    Parasitism,  383 

violet,   Common,  329 

violet,   Smooth,  329 

wood-sorrel,  306 

Yew  (See  ground-hemlock)  196 

Compared  with  pine,  194 

Resemblance  to  crowberry,      309 

Seed,  185 

Young,    Care  of  the,  525 

Zizia,  338 

Zonal  distribution  of  land  plants,       10 

distribution  of  water  plants,        12 

Zones,  Plant,  10,  13 


UNIVERSITY    OF    CALIFORNIA 
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